JP2015015575A - Image decoder, image encoder, image decoding method, image encoding method, image decoding program, and image encoding program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a prediction vector generation device that has a merge candidate deriving method which is compatible with a parallel decoding process and uses a preliminary parallax vector.SOLUTION: There is provided a device which decodes an image in encoding tree block units of predetermined size, and a parallax vector derivation part includes means of setting an adjacent vector of a block adjoining an object block as a parallax vector of the object block when the adjacent vector is usable, and setting a preliminary parallax vector as the parallax vector when the adjacent vector is not usable, and means of setting the adjacent vector as the preliminary parallax vector when the adjacent vector is not usable. The parallax vector derivation part has a preliminary parallax vector setting part which initializes the preliminary parallax vector at the point of time off a start of decoding of a first luminance encoding tree block of an encoding tree unit line when an entropy encoding synchronism flag is "1", and sets the parallax vector as the preliminary parallax vector when the adjacent block is usable.

Description

  The present invention relates to an image decoding device, an image encoding device, an image decoding method, an image encoding method, an image decoding program, and an image encoding program.

In motion compensation in encoding of multiple viewpoint images, the displacement between the target block and the corresponding block in another viewpoint image is derived as a disparity vector by using the disparity vector of an adjacent block, and the derived disparity vector is used. Thus, there is an encoding method for acquiring a corresponding block in another viewpoint image corresponding to the target block, and using a motion vector of the acquired corresponding block as a prediction vector of the target block. In Non-Patent Document 1, a block in which a prediction vector is generated as described above is called a DV-MCP (Motion Compensated Prediction) block (also referred to as a displacement motion compensation block), and a DV-MCP block is used to generate a prediction vector. A technique is described in which parameters such as a used disparity vector are stored in association with a DV-MCP block and used to generate a prediction vector of a block adjacent to the block. Here, the disparity vector used to generate the stored prediction vector is referred to as a preliminary disparity vector.
On the other hand, Non-Patent Document 2 describes a technique for storing only one preliminary parallax vector in a slice. This reduces the memory for storing the preliminary parallax vector.

  H. The technology called WPP (Wavefront parallel processing) is described in the H.265 standard (Patent Document 3). WPP is a mechanism for parallel encoding / decoding each coding tree unit row. In WPP, the encoding / decoding process of each encoding tree unit row is executed by shifting the time by two encoding tree units, so that the upper encoding tree is located at the head of each encoding tree unit row. By copying the context after the processing of the second coding tree unit from the right of the unit row, a decrease in coding efficiency is suppressed.

  H. The technology called parallel merging is also described in the H.265 standard (Patent Document 3). Parallel merging is a mechanism for enabling decoding processing by merging blocks within a range determined by a parallel merge flag to be executed in parallel. In parallel merging, adjacent block within the range determined by the parallel merge flag is not used for merge candidate derivation (spatial merge candidate derivation), so that the merge candidate derivation process of each block is made independent.

“3D-HEVC Test Model 4”, Joint Collaborative Team on 3D Video Coding Extension Development of ITU-T SG16 WP3 and ISO / IEC JTC1 / SC29 / WG11, JCT3V-D1005 Qualcomm Incorporated, “CE2.h related: Derived disparity vector for 3D-HEVC” Joint Collaborative Team on 3D Video Coding Extensions of ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11, JCT3V-D0194 ITU-T, “H.265: High efficiency video coding”, 04/2013

  However, when the technique described in Non-Patent Document 2 is used, there is a problem that a plurality of encoded tree unit rows cannot be processed in parallel using the WPP described in Non-Patent Document 3 described above. Specifically, in order to obtain a preliminary disparity vector of a coding tree unit belonging to a certain coding tree unit row, all the coding tree units before the target tree unit are sequentially assigned to the slice to which the target coding belongs. It is necessary to decode and derive a preliminary disparity vector. That is, before decoding a certain coding tree unit row, all previous coding tree unit rows need to be decoded, and parallel processing cannot be performed.

  Further, when the technique described in Non-Patent Document 2 is used, there is a problem that the merge candidates in the parallel merge unit cannot be derived in parallel using the parallel merge described in Non-Patent Document 3 described above. Specifically, since the preliminary disparity vector is updated depending on whether or not the disparity vector is derived (whether the disparity vector is used) in the blocks in the parallel merge unit, the blocks in the range determined by the parallel merge flag are updated. There arises a problem that a dependency relationship is generated between them, and merge candidate derivation processing cannot be executed in parallel.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide an image decoding apparatus and an image that can achieve both parallelization of encoding / decoding processing and prediction vector generation using a preliminary disparity vector. An object is to provide an encoding device, an image decoding method, an image encoding method, an image decoding program, and an image encoding program.

  (1) The present invention has been made to solve the above-described problems, and one aspect of the present invention is an image decoding apparatus that decodes an image in units of a coding tree block of a predetermined size, An entropy decoding unit that decodes syntax elements from the data, and a disparity vector deriving unit that derives a disparity vector from an adjacent vector or a preliminary disparity vector that is a block vector adjacent to the target block, and the entropy decoding unit includes an entropy code When the encoding synchronization flag is decoded and the entropy encoding synchronization flag is 1, CABAC decoding processing is initialized at the start of decoding of the first luminance encoding tree block in the encoding tree unit row, and the disparity When the adjacent vector is available, the vector deriving unit converts the adjacent vector into the target block. A disparity vector of the image, and when the adjacent vector is not available, means for setting a spare disparity vector as a disparity vector; and when the adjacent vector is available, the adjacent vector is Means for setting as a disparity vector, and the disparity vector derivation unit, when the entropy coding synchronization flag is 1, at the start of decoding of the first luminance coding tree block of the coding tree unit row, It has a preliminary parallax vector setting unit that initializes a preliminary parallax vector and sets a parallax vector as the preliminary parallax vector when the adjacent block is available.

  (2) Further, another aspect of the present invention is the image decoding device according to (1), wherein the preliminary parallax vector setting unit initializes the preliminary parallax vector as a zero vector.

  (3) According to another aspect of the present invention, there is provided the image decoding apparatus according to (1), in which the spare disparity vector setting unit decodes a spare disparity vector one coding tree block row above. It is characterized by initializing with a preliminary disparity vector of a coded tree block.

  (4) According to another aspect of the present invention, there is provided the image decoding apparatus according to (3), wherein the spare vector setting unit includes a spare disparity vector that is the second one in the coding tree block row one level higher. Initialization is performed with a preliminary disparity vector of a decoded encoded tree block.

  (5) According to another aspect of the present invention, there is provided an image decoding apparatus that decodes an image in units of a coding tree block having a predetermined size, an entropy decoding unit that decodes syntax elements from encoded data; A disparity vector deriving unit for deriving a disparity vector from a vector of a block adjacent to the target block or a preliminary disparity vector, wherein the entropy decoding unit decodes a parallel merge level, and the disparity vector deriving unit includes the parallel merge level and Means for determining the availability of the vector of the adjacent block according to the coordinates of the block adjacent to the target block, and the disparity vector setting unit further comprises a preliminary disparity vector according to the value of the parallel merge level The derivation method is changed.

  (6) Further, another aspect of the present invention is the image decoding device according to (5), in which the disparity vector setting unit is configured such that the disparity of the target block only when the parallel merge level is 2 As a vector, a preliminary parallax vector is used.

  (7) According to another aspect of the present invention, there is provided the image decoding apparatus according to (5), wherein the disparity vector setting unit is a parallel merge area unit that is an area of a predetermined size determined by the parallel merge level. When the image is divided by the above, the preliminary disparity vector is updated at the time of decoding the head block of the parallel merge region.

  (8) According to another aspect of the present invention, there is provided the image decoding apparatus according to (7), wherein the disparity vector setting unit is a parallel merge area unit that is an area of a predetermined size determined by the parallel merge level. When the image is divided into two, the adjacent vector derived as a disparity vector in the preceding block is set as a preliminary disparity vector when the coordinates of the target block coincide with the coordinates of the parallel merge region. .

  (9) According to another aspect of the present invention, there is provided an image encoding device including the disparity vector setting unit according to any one of (1) to (8).

  (10) According to another aspect of the present invention, there is provided an image decoding method for decoding an image in units of an encoding tree block having a predetermined size, the first step of decoding syntax elements from encoded data, A second step of deriving a disparity vector from an adjacent vector or a preliminary disparity vector that is a vector of a block adjacent to the target block. In the first step, the entropy encoding synchronization flag is decoded and entropy encoding is performed. When the synchronization flag is 1, CABAC decoding processing is initialized at the start of decoding of the first luminance coding tree block in the coding tree unit row, and the adjacent vector is used in the second step. If possible, set the adjacent vector to the disparity vector of the target block, and if the adjacent vector is not available , When a preliminary disparity vector is set as a disparity vector and the adjacent vector is available, the adjacent vector is set as the preliminary disparity vector, and when the entropy encoding synchronization flag is 1, Initializing the spare disparity vector at the start of decoding of the first luminance coding tree block in the coding tree unit row, and setting the disparity vector as the spare disparity vector when the adjacent block is available It is characterized by.

  (11) According to another aspect of the present invention, there is provided an image decoding method for decoding an image in units of a coding tree block having a predetermined size, the first step of decoding syntax elements from encoded data, , Having a second process of deriving a disparity vector from a vector of a block adjacent to the target block or a preliminary disparity vector, decoding a parallel merge level in the first process, and decoding the parallel merge level in the second process The availability of a vector of the adjacent block is determined according to a merge level and the coordinates of a block adjacent to the target block, and the disparity vector setting unit further determines a preliminary disparity vector according to the value of the parallel merge level. The derivation method is changed.

  (12) According to another aspect of the present invention, there is provided a program for causing a computer to function as an image decoding device that decodes an image in units of a coding tree block having a predetermined size. The image decoding device includes: An entropy decoding unit that decodes syntax elements from the encoded data, and a disparity vector derivation unit that derives a disparity vector from an adjacent vector or a preliminary disparity vector that is a block vector adjacent to the target block, and the entropy decoding unit includes: When the entropy coding synchronization flag is decoded and the entropy coding synchronization flag is 1, initialization of the CABAC decoding process is performed at the start of decoding of the first luminance coding tree block in the coding tree unit row, The disparity vector deriving unit, when the adjacent vector is available, Means for setting a vector as a disparity vector of the target block and setting the spare disparity vector as a disparity vector when the adjacent vector is not available; and when the adjacent vector is available, the adjacent vector Is set as the preliminary disparity vector, and when the entropy coding synchronization flag is 1, the disparity vector deriving unit starts decoding the first luminance coding tree block of the coding tree unit row It is characterized by having a preliminary parallax vector setting unit that initializes the preliminary parallax vector at the time and sets the parallax vector as the preliminary parallax vector when the adjacent block is available.

  (13) According to another aspect of the present invention, there is provided a program for causing a computer to function as an image decoding device that decodes an image in units of a coding tree block having a predetermined size. An entropy decoding unit that decodes syntax elements from the encoded data, and a disparity vector derivation unit that derives a disparity vector from a vector of a block adjacent to the target block or a preliminary disparity vector, and the entropy decoding unit has a parallel merge level And the disparity vector deriving unit includes means for determining availability of the vector of the adjacent block according to the parallel merge level and the coordinates of the block adjacent to the target block, and further, the disparity vector setting Change the method for deriving the preliminary disparity vector according to the value of the parallel merge level And wherein the Rukoto.

  According to the present invention, it is possible to achieve both encoding / decoding processing in parallel and prediction vector generation using a preliminary disparity vector.

1 is a schematic block diagram illustrating a configuration of an image transmission system 10 according to a first embodiment of the present invention. It is a figure explaining the encoding tree unit in the embodiment. It is a figure which shows the example of a division | segmentation into the prediction unit of the encoding tree block in the embodiment. It is a schematic block diagram which shows the structure of the image decoding apparatus 300 in the embodiment. It is a schematic block diagram which shows the structure of the inter prediction parameter decoding part 341 in the same embodiment. It is a schematic block diagram which shows the structure of the merge prediction parameter derivation | leading-out part 344 in the embodiment. It is a figure explaining the position of the adjacent prediction unit which the parallax vector derivation | leading-out part 382 and the spatial merge candidate derivation | leading-out part 383 in the embodiment search. It is a figure explaining the prediction unit which the time merge candidate derivation | leading-out part 384 in the embodiment searches. It is a conceptual diagram (the 1) explaining operation | movement of the interview merge candidate derivation | leading-out part 381 in the embodiment. It is a conceptual diagram (the 2) explaining operation | movement of the inter view merge candidate derivation | leading-out part 381 in the embodiment. It is a conceptual diagram of WPP in the same embodiment. It is a flowchart (the 1) explaining operation | movement of the merge prediction parameter derivation | leading-out part 344 in the embodiment. It is a flowchart explaining operation | movement of the merge prediction parameter derivation | leading-out part 344 in step Sz4 in the same embodiment. It is a flowchart explaining the process in step Sa3 in the same embodiment. It is a flowchart explaining the process in step Sb1 in the same embodiment. It is a schematic block diagram which shows the structure of the image coding apparatus 100 in the embodiment. It is a schematic block diagram which shows the structure of the merge prediction parameter derivation | leading-out part 344a in the same embodiment. It is a flowchart explaining operation | movement of the merge prediction parameter derivation | leading-out part 344a in the same embodiment. It is a conceptual diagram of the parallel merge in the same embodiment. It is a schematic block diagram which shows the structure of the image decoding apparatus 300b by 3rd Embodiment of this invention. It is a schematic block diagram which shows the structure of the merge prediction parameter derivation | leading-out part 344b in the same embodiment. It is a flowchart explaining operation | movement of the merge prediction parameter derivation | leading-out part 344b in the same embodiment. It is a flowchart explaining the process in step Sa3 'in the same embodiment. It is a flowchart explaining the process in step Sb1 'in the same embodiment. It is a schematic block diagram which shows the structure of the merge prediction parameter derivation | leading-out part 344c in the same embodiment. It is a flowchart explaining the process in step Se1 '' in the embodiment.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block diagram illustrating a configuration of an image transmission system 10 according to the present embodiment. The image transmission system 10 is a system that encodes and transmits a plurality of viewpoint images, and displays an image using these at the transmission destination. As shown in FIG. 1, the image transmission system 10 includes an image encoding device 100, a network 200, an image decoding device 300, and an image display device 400. In the present embodiment, when the prediction vector is generated, in the first coding tree unit of each coding tree unit row, the stored spare disparity vector is a vector (zero vector) in which both the X component and the Y component are zero. By resetting, when using WPP (Wavefront parallel processing), parallel encoding / decoding processing of each encoding tree unit row is realized in the image encoding device 100 and the image decoding device 300 using the preliminary disparity vector. ing.

  The image encoding device 100 encodes each of a plurality of viewpoint images (also referred to as texture images) T, and generates an encoded stream Te of each viewpoint image T. Note that the image encoding device 100 encodes at least one of the plurality of viewpoint images T as a reference viewpoint image (also referred to as a base view), and other than the non-reference viewpoint images (non-base view (non-base view)). It is also encoded as Non base view). The reference viewpoint image is a viewpoint image that cannot use parallax prediction at the time of encoding, and the non-reference viewpoint image is a viewpoint image that can use parallax prediction at the time of encoding. . Usually, the layer ID = 0 is used for the reference viewpoint image, and a layer ID other than 0 is used for the non-reference viewpoint image. The viewpoint image is a moving image from a specific viewpoint, and is composed of pictures that are images at each time.

  The network 200 is a network such as an IP (Internet Protocol) network or a cable television network that transmits the encoded stream Te to the image decoding device 300. The encoded stream Te may be transmitted by a network as in the present embodiment, but may be transmitted by a broadcast wave such as terrestrial digital broadcast or satellite broadcast, or a DVD (Digital Versatile Disc), Blu-ray ( It may be transmitted by a recording medium such as Blu-ray (registered trademark).

  The image decoding device 300 decodes the encoded stream Te transmitted by the network 200, and generates a decoded viewpoint image Td. The image display device 400 generates an image using the decoded viewpoint image Td generated by the image decoding device 300. The image display apparatus 400 includes a display device such as a liquid crystal display for displaying an image or an organic EL (electroluminescence) display. Note that the image displayed by the image display device 400 may be a two-dimensional image or a stereoscopic image.

  FIG. 2 is a diagram illustrating the coding tree unit. As shown in FIG. 2, the image encoding apparatus 100 divides and encodes a picture pic into 64 × 64 pixel coding tree units CTU11, CTU12,. The image decoding apparatus 300 obtains a picture pic by decoding and joining the coding tree units CTU11, CTU12,..., CTUMN. The order of the encoding process and the order of the decoding process are the same, as shown by the arrow arw in FIG. The encoding tree unit CTU11 at the upper left end of the picture pic is first processed. Next is a coding tree unit CTU12 on the right side of the coding tree unit CTU11. Subsequently, the encoding tree unit adjacent to the right of the processed encoding tree unit is sequentially processed until the rightmost encoding tree unit CTU1N is reached.

  When the coding tree units CTU11 to CTU1N are processed, the coding tree units CTU21 to CTU2N one level below are processed in order from the left end. Similarly, when the encoding tree units CTU21 to CTU2N are processed, the encoding tree units CTU31 to CTU3N one stage below are sequentially processed from the left end. In this way, the encoding tree units at each stage are processed until the encoding tree units CTUM1 to CUMN at the bottom stage of the picture pic are processed.

  In an image composed of luminance and color difference, the coding tree unit includes a coding tree block having three color components. The luminance encoding tree block and the color difference encoding tree block are processed in this order. FIG. 3 is a diagram illustrating an example of dividing an encoding tree block into prediction units (Prediction Units). The image coding apparatus 100 converts each coding tree unit into a coding unit (Coding Unit) having a size of 64 pixels × 64 pixels, 32 pixels × 32 pixels, 16 pixels × 16 pixels, or 8 pixels × 8 pixels. ). Furthermore, each encoding unit is divided into prediction units using any of a plurality of predetermined patterns.

  The prediction unit is a unit in which the image encoding device 100 and the image decoding device 300 generate a prediction image. Therefore, the prediction unit is also a unit by which the image encoding device 100 and the image decoding device 300 acquire a motion vector and a disparity vector (displacement vector). In the example illustrated in FIG. 3, the coding tree unit CTU1 is divided into prediction units PU1 to PU21. The smallest horizontal width in the shape of the prediction unit is, for example, four pixels such as the prediction units PU18 and PU19. Further, the smallest height in the shape of the prediction unit is, for example, four pixels such as the prediction units PU8, PU9, and PU21.

The image encoding device 100 and the image decoding device 300 according to the present embodiment can perform parallel encoding / decoding processing for each encoding tree unit row by using WPP (Wavefront Parallel Processing). FIG. 11 is a conceptual diagram for explaining WPP. As indicated by arrows arw1 to 5 in FIG. 11, the image decoding device 300 decodes each coding tree unit row in parallel. However, the decoding processing of the second and subsequent coding tree unit rows starts with a delay of two coding tree units from the coding tree unit row on the first row. This is because the context necessary for decoding the first coding tree unit in the coding tree unit row by CABAC is initialized with the value at the end of decoding the coding tree unit adjacent to the upper right. . For example, after encoding / decoding processing of two encoding tree units from the beginning of the encoding tree unit row corresponding to arw4, before starting processing of the encoding tree unit row corresponding to arw5, the first encoding tree FIG. 4 is a schematic block diagram showing the configuration of the image decoding apparatus 300. The context necessary for encoding / decoding the unit currCTU with CABAC is copied from the encoding tree unit CTU_TR adjacent to the upper right of the currCTU. As illustrated in FIG. 4, the image decoding apparatus 300 includes an entropy decoding unit 301, an inverse quantization / inverse DCT (Discrete Cosine Transform) conversion unit 302, an addition unit 303, a prediction parameter decoding unit 304, and a prediction image generation. A unit 305 and a reference image memory 306 are included. The prediction parameter decoding unit 304 includes an inter prediction parameter decoding unit 341 (prediction vector generation device) and an intra prediction parameter decoding unit 342. The predicted image generation unit 305 includes an inter predicted image generation unit 351 and an intra predicted image generation unit 352. The reference image memory 306 includes an image memory 361 and a prediction parameter memory 362.

  The entropy decoding unit 301 performs entropy decoding on the encoded stream Te. The entropy decoding unit 301 inputs the quantized coefficient obtained by entropy decoding to the inverse quantization / inverse DCT transform unit 302, inputs the transmission prediction parameter tp to the prediction parameter decoding unit 304, and sets the prediction mode predMode to the predicted image. Input to the generation unit 305. The entropy decoding unit 301 decodes the entropy coding synchronization flag entropy_coding_sync_enabled_flag, and when the entropy coding synchronization flag entropy_coding_sync_enabled_flag is 1, at the start of decoding of the first luminance coding tree block in the coding tree unit row, CABAC Initialize the decryption process. The entropy decoding unit 301 also inputs an entropy encoding synchronization flag entropy_coding_sync_enabled_flag to the inter prediction parameter decoding unit 341. The transmission prediction parameter tp is a prediction parameter that is included in the encoded stream Te and transmitted from the image encoding device 100 to the image decoding device 300. The prediction parameter is a parameter for generating a prediction image of a prediction unit obtained by dividing the viewpoint image T. The prediction mode predMode is a kind of transmission prediction parameter tp, and is information that specifies a prediction mode for generating a prediction image of each prediction unit. In the present embodiment, as an example, a case where there is inter prediction and intra prediction as the prediction mode predMode will be described, but other modes such as a skip mode may be included. The entropy encoding synchronization flag entropy_coding_sync_enabled_flag is a flag (a flag indicating that WPP processing is possible) indicating that each decoding tree unit row can be decoded in parallel. When the entropy coding synchronization flag entropy_coding_sync_enabled_flag is true, it is possible to start a decoding process for a certain coding tree unit row with a delay of two coding tree units from the coding tree unit row on the first row.

  The inverse quantization / inverse DCT transform unit 302 inversely quantizes the quantization coefficient to obtain a DCT coefficient. The inverse quantization / inverse DCT transform unit 302 performs inverse DCT transform on the DCT coefficients to generate a difference image. The addition unit 303 adds the predicted image P generated by the predicted image generation unit 305 and the difference image generated by the inverse quantization / inverse DCT conversion unit 302 to generate a decoded viewpoint image Td. The adding unit 303 stores each picture of the generated decoded viewpoint image Td in the image memory 361 as a reference picture. Here, the addition of the predicted image P and the difference image is to add the pixel value of the pixel at the same position in the difference image to the pixel value of each pixel of the predicted image P.

  The prediction parameter decoding unit 304 uses the transmission prediction parameter tp to generate a prediction parameter for generating the prediction image P of each prediction unit. The prediction parameter decoding unit 304 refers to the prediction mode predMode to determine the prediction mode of each prediction unit. For a prediction unit that is inter prediction, the inter prediction parameter decoding unit 341 derives a prediction parameter, and intra prediction is performed. For a certain prediction unit, an intra prediction parameter decoding unit 342 derives a prediction parameter. The inter prediction parameter decoding unit 341 inputs the derived prediction parameter to the prediction image generation unit 305 and stores it in the prediction parameter memory 362.

  The inter prediction parameter decoding unit 341 of the prediction parameter decoding unit 304 derives a reference picture index refIdxLX and a vector mvLX, which are prediction parameters of a prediction unit whose prediction mode is inter prediction. When the inter prediction parameter decoding unit 341 derives the reference picture index refIdxLX and the vector mvLX, the entropy coding synchronization flag entropy_coding_sync_enabled_flag and the prediction parameter memory 362 are stored in addition to the transmission prediction parameter tp input from the entropy decoding unit 301 The already decoded prediction parameters are used. Details of the method for generating the vector mvLX will be described later.

  The inter prediction parameter decoding unit 341 inputs the derived reference picture index refIdxLX and the vector mvLX for each prediction unit whose prediction mode is inter prediction to the prediction image generation unit 305 and stores it in the prediction parameter memory 362.

  Here, the reference picture index refIdxLX indicates either the reference picture index refIdxL0 or refIdxL1.

  The reference picture index refIdxL0 is an index indicating a reference picture in the reference picture list L0. The reference picture index refIdxL1 is an index indicating a reference picture in the reference picture list L1. The reference picture list is a list of pictures decoded before the decoding target picture.

  Similarly, the vector mvLX is a vector for the reference picture of the reference list picture LX, and the same applies to other codes including “LX”. A case where the prediction image of the target unit is generated from a reference picture of a picture at the same viewpoint as the target picture to which the target unit belongs is called motion prediction. A case where the prediction image of the target unit is generated from a reference picture of a picture with a different viewpoint from the target picture to which the target unit belongs is called parallax prediction. Note that the vector mvLX is a layer of the reference picture RefPicListX [refIdxLX] specified by the reference picture index refIdxLX and the reference picture list RefPicListX attached to the vector mvLX when the prediction image of the target prediction unit is generated by motion prediction. When IDnal_layer_id is the same as the layer IDnal_layer_id of the target picture, it is a motion vector, and when generated by disparity prediction, that is, the layer IDnal_layer_id of the reference picture RefPicListX [refIdxLX] accompanying the vector mvLX Is different from the disparity vector. That is, the motion vector is a motion vector when the layer IDs of the target picture and the reference picture match, and a disparity vector when they do not match. The motion vector and the disparity vector may be collectively referred to as a motion vector.

  It should be noted that the motion vector and the disparity vector may be discriminated by using a view index or POC regardless of the layer ID. Specifically, a case where the view index of the target picture and the reference picture match may be determined as a motion vector, and a case where they do not match may be determined as a disparity vector. In addition, a case where the POC of the target picture and the reference picture do not match may be determined as a motion vector, and a case where they match, a disparity vector may be determined.

  The intra prediction parameter decoding unit 342 derives an intra prediction parameter with reference to the prediction parameter stored in the prediction parameter memory 362 based on the code input from the entropy decoding unit 301, for example, the prediction mode PredMode. The intra prediction parameter is a prediction parameter used in a process of predicting a prediction unit within a picture, for example, an intra prediction mode IntraPredMode. The intra prediction parameter decoding unit 342 outputs the decoded intra prediction parameter to the intra prediction image generation unit 352 and stores it in the prediction parameter memory 362.

  The predicted image generation unit 305 generates a predicted image P of each prediction unit and inputs it to the adding unit 303. The prediction image generation unit 305 refers to the prediction mode predMode to determine the prediction mode of each prediction unit, and for the prediction unit that is inter prediction, the inter prediction image generation unit 351 generates the prediction image P, and performs intra prediction. For the prediction unit, the intra predicted image generation unit 352 generates the predicted image P.

  The inter prediction image generation unit 351 reads out a corresponding block from the reference picture stored in the image memory 361 for each prediction unit that is inter prediction, and sets it as a prediction image P. The inter prediction image generation unit 351 specifies the above-described corresponding block with reference to the reference picture index refIdxLX input from the inter prediction parameter decoding unit 341 and the vector mvLX.

  The intra prediction image generation unit 352 performs intra prediction specified by the intra prediction mode intraPredMode input from the intra prediction parameter decoding unit 342 for each prediction unit that is intra prediction, and generates a prediction image P. When generating the predicted image P of the prediction unit, the intra predicted image generation unit 352 reads the pixel value of the pixel adjacent to the prediction unit from the image memory 361 and generates the predicted image P using the pixel value. . In addition, the production | generation of the estimated image P by the intra estimated image generation part 352 can use the production | generation method of the predicted image by well-known intra prediction.

  The image memory 361 of the reference image memory 306 stores each picture of the decoded viewpoint image Td generated by the addition unit 303 as a reference picture. Further, the prediction parameter memory 362 of the reference image memory 306 stores the prediction parameter input from the prediction parameter decoding unit 304.

  FIG. 5 is a schematic block diagram illustrating a configuration of the inter prediction parameter decoding unit 341. The inter prediction parameter decoding unit 341 includes an inter prediction parameter extraction unit 343, a merge prediction parameter derivation unit 344, an AMVP (Advanced Motion Vector Prediction) prediction parameter derivation unit 345, and an addition unit 346. The AMVP prediction parameter derivation unit 345 includes a vector candidate derivation unit 347 and a prediction vector selection unit 348.

  The inter prediction parameter extraction unit 343 refers to the transmission prediction parameter tp input from the entropy decoding unit 301 and determines whether the prediction parameter derivation method is merge prediction or AMVP prediction for each inter prediction unit. judge. The inter prediction parameter extraction unit 343 extracts the merge index merge_idx related to the prediction unit from the transmission prediction parameter tp for the prediction unit that is the merge prediction, and inputs the merge index merge_idx to the merge prediction parameter derivation unit 344. Moreover, the inter prediction parameter extraction part 343 decodes the reference picture index refIdxLX, the difference vector mvdLX, and the prediction vector index mvp_LX_idx from the transmission prediction parameter tp about the prediction unit which is AMVP prediction. The inter prediction parameter extraction unit 343 inputs the reference picture index refIdxLX and the prediction vector index mvp_LX_idx to the AMVP prediction parameter derivation unit 345, and inputs the difference vector mvdLX to the addition unit 346.

  The merge prediction parameter derivation unit 344 refers to the entropy coding synchronization flag entropy_coding_sync_enabled_flag input from the entropy decoding unit 301 and the prediction parameter memory 362, and is determined in advance for each prediction unit whose prediction parameter derivation method is merge prediction. A plurality of prediction parameter candidates are generated according to the rules. The merge prediction parameter derivation unit 344 sets the prediction parameter candidate indicated by the merge index merge_idx among the plurality of generated prediction parameter candidates for each prediction unit that is merge prediction, in the vector mvLX and the reference picture index refIdxLX. The merge prediction parameter derivation unit 344 refers to the vector mvLX and the reference picture index refIdxLX stored in the prediction parameter memory 362 when generating prediction parameter candidates.

  The vector candidate derivation unit 347 of the AMVP prediction parameter derivation unit 345 generates a plurality of vector candidates according to a predetermined rule for each prediction unit whose prediction parameter derivation method is AMVP prediction with reference to the prediction parameter memory 362. To do. At this time, the vector candidate derivation unit 347 uses the reference picture index refIdxLX input from the inter prediction parameter extraction unit 343 to generate a prediction image by motion prediction for each prediction unit whose prediction parameter derivation method is AMVP prediction. It is determined whether the prediction unit is a prediction unit to generate or a prediction unit to generate a prediction image by parallax prediction.

  Specifically, when the reference picture index refIdxLX indicates a picture at the same time as the picture to which the prediction unit belongs, the vector candidate deriving unit 347 generates a prediction image by using the prediction unit based on parallax prediction. It is determined that When a picture at a different time is indicated, the vector candidate deriving unit 347 determines that the prediction unit is a prediction unit that generates a prediction image by motion prediction. The rules used when the vector candidate deriving unit 347 generates vector candidates are the prediction unit that generates a prediction image by parallax prediction when the prediction unit determines that the prediction unit is a prediction unit that generates a prediction image by motion prediction. It is changed when it is determined that there is.

  For each prediction unit in which the prediction parameter derivation method is AMVP prediction, the prediction vector selection unit 348 sets the vector candidate indicated by mvp_LX_idx among the plurality of vector candidates generated by the vector candidate derivation unit 347 as the prediction vector mvp. The addition unit 346 adds the prediction vector mvp generated by the prediction vector selection unit 348 and the difference vector mvdLX input from the inter prediction parameter extraction unit 343 to generate a vector mvLX. The vector mvLX is input to the inter predicted image generation unit 351 and the prediction parameter memory 362 together with the reference picture index refIdxLX extracted by the inter prediction parameter extraction unit 343.

  FIG. 6 is a schematic block diagram illustrating a configuration of the merge prediction parameter deriving unit 344. The merge prediction parameter derivation unit 344 includes a merge candidate derivation unit 371 and a merge candidate selection unit 372. The merge candidate derivation unit 371 includes a merge candidate storage unit 373, a merge candidate derivation control unit 374, an extended merge candidate derivation unit 375, and a basic merge candidate derivation unit 376. The extended merge candidate derivation unit 375 includes an inter-view merge candidate derivation unit 381 and a disparity vector derivation unit 382. The disparity vector deriving unit 382 includes a spare disparity vector setting unit 387 and a spare disparity vector storage unit 388. The basic merge candidate derivation unit 376 includes a spatial merge candidate derivation unit 383, a temporal merge candidate derivation unit 384, a combined merge candidate derivation unit 385, and a zero merge candidate derivation unit 386.

  When the disparity vector deriving unit 382 is decoding the non-reference viewpoint image, the disparity vector deriving unit 382 searches for a prediction unit adjacent to the processing target prediction unit in a predetermined order, and obtains a vector mvLX that is a disparity vector. The prediction unit having is detected. That is, the reference picture index refIdxLX of the adjacent prediction unit is checked, and the adjacent prediction unit whose layer IDnal_layer_id (view IDview_id) of the reference picture RefPicListX [refIdxLX] indicated by the reference picture index refIdxLX is different from the target block is the layer IDnal_layer_id (view IDview_id) Is detected. However, when an adjacent prediction unit having the vector mvLX that is a disparity vector has already been detected, the subsequent adjacent prediction units do not perform the detection process. Note that the prediction unit to be searched is not limited to the prediction unit adjacent to the processing target prediction unit. For example, a prediction unit adjacent to a coding unit (CU) or a coding tree unit (CTU) to which the prediction unit to be processed belongs may be used.

  The disparity vector deriving unit 382 reads the vector mvLX of the prediction unit and the reference picture index refIdxLX from the prediction parameter memory 362 when the vector mvLX that is the disparity vector exists in the searched prediction unit, and the vector mvLX is read out from the prediction parameter memory 362. And input to the inter-view merge candidate derivation unit 381 together with the reference picture index refIdxLX, input the disparity vector mvDisp as the preliminary disparity vector mvDDV to the preliminary disparity vector storage unit 388, and the availability (availableDV) of the disparity vector mvDisp Set to true. Also, the disparity vector deriving unit 382 reserves a spare when the availability (availableDV) of the disparity vector mvDisp is false, that is, when there is no prediction unit having the vector mvLX that is the disparity vector in the searched prediction unit. The preliminary disparity vector mvDDV read from the disparity vector storage unit 388 is used as the disparity vector mvDisp, and together with the reference picture index refIdxLX indicating the picture of the reference viewpoint image at the same time as the picture to which the prediction unit belongs, the inter-view merge candidate derivation unit 381 To enter. Note that the parallax vector deriving unit 382 does not operate when the reference viewpoint image is decoded.

  The preliminary disparity vector setting unit 387 included in the disparity vector deriving unit 382 has the entropy encoding synchronization flag entropy_coding_sync_enabled_flag true, and the encoding tree unit to be processed is the code of the first luminance value of the encoding tree unit row. In the case of a modified tree block, a zero vector is set in the preliminary parallax vector mvDDV as shown in the following equation and stored in the preliminary parallax vector storage unit 388.

mvDDV = (0,0)
The above equation can also be expressed as mvDDV [0] = 0 and mvDDV [1] = 0 by dividing the X component and the Y component.

  In addition, even when the encoding tree unit to be processed is the head of the slice, a zero vector is set in the spare disparity vector mvDDV.

  The inter-view merge candidate derivation unit 381 uses the disparity vector mvDisp input from the disparity vector derivation unit 382 and the reference picture index refIdxLX, and corresponds to the processing target prediction unit from the pictures indicated by the reference picture index refIdxLX. When a prediction unit is specified and the corresponding prediction unit has a vector mvLX that is a motion vector, the vector mvLX and the reference picture index refIdxLX of the vector mvLX are stored in the merge candidate storage unit 373 as extended merge candidates To do. The extended merge candidate is a kind of prediction parameter candidate.

  On the other hand, the inter-view merge candidate derivation unit 381 expands the disparity vector mvDisp input from the disparity vector derivation unit 382 and the reference picture index refIdxLX when the corresponding prediction unit does not have the vector mvLX that is a motion vector. Derived as a merge candidate. Examples where the corresponding prediction unit does not have the vector mvLX that is a motion vector include a case where the corresponding prediction unit is a prediction unit that generates a prediction image by parallax prediction, or a prediction unit that generates a prediction image by intra prediction. There is a case. Further, the inter-view merge candidate derivation unit 381 does not operate when the reference viewpoint image is being decoded.

  The merge candidate derivation control unit 374 has a spatial merge candidate derivation unit 383, a temporal merge candidate derivation unit 384, a combined merge candidate derivation unit 385, and a zero merge candidate derivation so that a predetermined number (here, five) of basic merge candidates can be obtained. The operation of the unit 386 is controlled. The basic merge candidate is a kind of prediction parameter candidate.

  The spatial merge candidate derivation unit 383 searches for adjacent prediction units adjacent to the processing target prediction unit in a predetermined order, and detects up to four prediction units having the vector mvLX. The spatial merge candidate derivation unit 383 stores the detected prediction unit vector mvLX and the reference picture index refIdxLX in the merge candidate storage unit 373 as a spatial merge candidate that is a kind of basic merge candidate.

  The temporal merge candidate derivation unit 384 performs the order of the prediction unit including the prediction unit adjacent to the lower right end of the processing target prediction unit and the center of the processing target prediction unit in the picture whose reference picture index refIdxLX is “0”. And a maximum of one prediction unit having the vector mvLX is detected. The temporal merge candidate derivation unit 384 stores the detected prediction unit vector mvLX and the reference picture index refIdxLX in the merge candidate storage unit 373 as a temporal merge candidate which is a kind of basic merge candidate.

  The merge merge candidate derivation unit 385, when the number of basic merge candidates stored in the merge candidate storage unit 373 by the spatial merge candidate derivation unit 383 and the temporal merge candidate derivation unit 384 is less than five, The merge candidates are combined by a predetermined method to generate a new basic merge candidate and stored in the merge candidate storage unit 373.

  When the number of basic merge candidates stored in the merge candidate storage unit 373 by the spatial merge candidate derivation unit 383, the temporal merge candidate derivation unit 384, and the merge merge candidate derivation unit 385 is less than five, The zero vectors are stored in the merge candidate storage unit 373 as basic merge candidates so that there are five basic merge candidates.

  The merge candidate storage unit 373 stores the basic merge candidate generated by the basic merge candidate derivation unit 376 and the extended merge candidate generated by the extended merge candidate derivation unit 375.

  The merge candidate selection unit 372 selects the one specified by the merge index merge_idx input from the inter prediction parameter extraction unit 343 from the basic merge candidates and the extended merge candidates stored in the merge candidate storage unit 373, and the vector mvLX And the reference picture index refIdxLX are input to the inter predicted image generation unit 351 and the prediction parameter memory 362.

FIG. 7 is a diagram for explaining the positions of adjacent prediction units searched by the spatial merge candidate derivation unit 383. In FIG. 7, the prediction unit PU1 is a prediction unit to be processed. The prediction units A ₀ , A ₁ , B ₀ , B ₁ , B ₂ are adjacent prediction units searched by the spatial merge candidate derivation unit 383. As shown in FIG. 7, adjacent prediction unit A ₀ is a prediction unit adjacent to the lower left of the prediction unit PU1 to be processed. Adjacent prediction unit A _1, of the prediction unit adjacent to the left of the prediction unit PU1 to be processed, a prediction unit located at the bottom.

Adjacent prediction unit B ₀ is a prediction unit adjacent to the upper right of the prediction unit PU1 to be processed. Adjacent prediction unit B ₁ represents, among the prediction unit adjacent to the top of the prediction unit PU1 to be processed, a prediction unit located rightmost. Adjacent prediction unit B ₂ is a prediction unit adjacent to the top left of the prediction unit PU1 to be processed. In this embodiment, the search order of the spatial merge candidate derivation unit 383 is the order of the adjacent prediction units A ₁ , B ₁ , B ₀ , A ₀ , B ₂ , but other orders may be used. It should be noted that when the prediction unit PU1 to be processed is in the upper end of the coding tree block, of the adjacent prediction unit _{A 0,} A _1, B _0, B 1, _{B 2,} adjacent prediction unit _{B 0, B} 1, B ₂ is a prediction unit above the coding tree block.

When the coordinates of the upper left pixel of the prediction unit PU1 to be processed are (xP, yP), the width is nPbW, and the height is nPbH, the adjacent prediction units A ₀ , A ₁ , B ₀ , B ₁ , B ₂ is a prediction unit that includes the following coordinates.

Adjacent prediction unit A ₀ : (xP-1, yP + nPbH)
Adjacent prediction unit A ₁ : (xP-1, yP + nPbH-1)
Adjacent prediction unit B ₀ : (xP + nPbW, yP−1)
Adjacent prediction unit B ₁ : (xP + nPbW−1, yP−1)
Adjacent prediction unit _{B 2: (xP-1,} yP-1)
Note that the search target in the disparity vector deriving unit 382 is not limited to the adjacent prediction unit similar to the spatial merge candidate deriving unit 383. For example, a prediction unit adjacent to the coding unit CU to which the processing target prediction unit belongs may be searched. When searching for a prediction unit adjacent to the encoding unit, when the coordinates of the upper left pixel of the encoding unit CU to which the prediction unit to be processed belongs is (xC, yC) and the size of the encoding unit is nCS, Adjacent prediction units A ₀ , A ₁ , B ₀ , B ₁ , B ₂ are prediction units each including the following coordinates.

Adjacent prediction unit A ₀ : (xC-1, yC + nCS)
Adjacent prediction unit A ₁ : (xC-1, yC + nCS-1)
Adjacent prediction unit B ₀ : (xC + nCS, yC−1)
Adjacent prediction unit B ₁ : (xC + nCS−1, yC−1)
Adjacent prediction unit _{B 2: (xC-1,} yC-1)
FIG. 8 is a diagram for explaining the prediction unit searched by the temporal merge candidate derivation unit 384. In FIG. 8, a picture pic1 is a picture whose reference picture index refIdxLX has a value of “0”. The block PU1 ′ is an area having the same coordinates as the processing target prediction unit PU1 in the picture pic1. The prediction unit Center is a prediction unit including the center coordinates of the prediction unit PU1 in the picture pic1. The prediction unit RB is a prediction unit adjacent to the lower right end of the block PU1 ′. The prediction unit RB includes coordinates (xP + nPbW, yP + nPbH) where the coordinates of the upper left pixel of the processing target prediction unit PU1 are (xP, yP), the width is nPbW, and the height is nPbH. It is.

9 and 10 are conceptual diagrams illustrating the operation of the inter-view merge candidate derivation unit 381. In FIG. 9, a picture pic2 is a picture to be processed. The prediction unit PU1 is a processing target prediction unit. The point Ct is the center of the prediction unit PU1. Prediction units A ₀ , A ₁ , B ₀ , B ₁ , B ₂ are adjacent prediction units shown in FIG. 7 ′. Disparity vector Dv is a vector mvLX a disparity vector of the neighboring prediction unit _{B 0.} In FIG. 10, a picture pic3 is a reference picture to which the disparity vector Dv refers. The point Ct ′ is a point having the same coordinates as the point Ct. The prediction unit PU2 is a prediction unit including a point indicated by the disparity vector Dv when the point Ct is the starting point. The motion vector Mv is a vector mvLX that is a motion vector of the prediction unit PU2. When the disparity vector derivation unit 382 receives the disparity vector Dv shown in FIG. 9 from the disparity vector derivation unit 382, the inter-view merge candidate derivation unit 381 identifies the prediction unit PU2 as a corresponding prediction unit and sets the motion vector Mv as an extended merge candidate.

  FIG. 12 is a flowchart for explaining the operation of the merge prediction parameter deriving unit 344. The merge prediction parameter deriving unit 344 merges candidates for each prediction unit PU in the coding unit CU included in each coding tree unit CTU in the process of processing the coding tree units CTU in the picture in the raster scan order. Is derived. Specifically, the process from step Sz2 to step Sz4 is performed on each CTU with the interval between step Sz1 and step Sz5 as a CTU loop (Sz1, Sz5). The spare disparity vector setting unit 387 included in the merge prediction parameter derivation unit 344 has an entropy encoding synchronization flag entropy_coding_sync_enabled_flag that is true, and the encoding tree unit to be processed has the luminance value at the head of the encoding tree unit row. If it is an encoded tree block (Sz2-Yes), a zero vector is set to the preliminary disparity vector mvDDV (Sz3). Next, the merge prediction parameter deriving unit 344 derives merge candidates for each prediction unit PU in each coding unit CU included in the coding tree unit CTU (Sz4). A detailed description of the derivation method will be described later.

  FIG. 13 is a flowchart for explaining step Sc5 in FIG. The merge candidate selection unit 372 acquires the merge index merge_idx extracted by the inter prediction parameter extraction unit 343 (Sa1). The merge candidate derivation control unit 374 determines whether or not the viewpoint image to be decoded is a non-reference viewpoint image (Sa2). When the image is a non-reference viewpoint image (Sa2-Yes), the merge candidate derivation control unit 374 instructs the extended merge candidate derivation unit 375 to derive the extended merge candidate. Upon receiving the instruction, the extended merge candidate derivation unit 375 derives an extended merge candidate and stores it in the merge candidate storage unit 373 (Sa3).

  When it is determined in step Sa2 that the image is not a non-reference viewpoint image (Sa2-No) or after the processing in step Sa3, the merge candidate derivation control unit 374 instructs the spatial merge candidate derivation unit 383 to derive a spatial merge candidate. Upon receiving the instruction, the spatial merge candidate derivation unit 383 derives a spatial merge candidate and stores it in the merge candidate storage unit 373 (Sa4). Next, the merge candidate derivation control unit 374 instructs the time merge candidate derivation unit 384 to derive the time merge candidate. Upon receiving the instruction, the time merge candidate derivation unit 384 derives a time merge candidate and stores it in the merge candidate storage unit 373 (Sa5).

  Next, the merge candidate derivation control unit 374 refers to the prediction parameter candidates (merge candidates) stored in the merge candidate storage unit 373, and deletes one of them when the stored ones match ( Sa6). Next, the merge candidate derivation control unit 374 determines whether the number of prediction parameter candidates stored in the merge candidate storage unit 373 is less than a predetermined threshold (Sa7). When it is less than the threshold (Sa7-Yes), the merge candidate derivation control unit 374 instructs the merge merge candidate derivation unit 385 to derive merge merge candidates. Upon receiving the instruction, the merge merge candidate derivation unit 385 derives a merge merge candidate and stores it in the merge candidate storage unit 373 (Sa8).

  Next, the merge candidate derivation control unit 374 determines again whether the number of prediction parameter candidates stored in the merge candidate storage unit 373 is less than a predetermined threshold (Sa9). When it is less than the threshold (Sa9-Yes), the merge candidate derivation control unit 374 instructs the zero merge candidate derivation unit 386 to derive the zero merge candidate. When receiving the instruction, the zero merge candidate derivation unit 386 derives zero merge candidates and stores them in the merge candidate storage unit 373 until the number of prediction parameter candidates becomes equal to the threshold value (Sa10).

  When it is determined in steps Sa7 and Sa9 that the number of prediction parameter candidates is not less than a predetermined threshold (Sa7-No, Sa9-No) or after the processing of step Sa10, the merge candidate selection unit 372 includes a merge candidate storage unit. A prediction parameter candidate designated by the merge index merge_idx acquired in step Sa1 is selected from the prediction parameter candidates stored in 373 (Sa11). Next, the merge candidate selection unit 372 outputs prediction parameters such as the vector mvLX and the reference picture index refIdxLX (Sa15), and ends the process.

  FIG. 14 is a flowchart for explaining the processing in step Sa3 in FIG. The disparity vector derivation unit 382 of the extended merge candidate derivation unit 375 derives the disparity vector mvDisp (Sb1). A detailed derivation method will be described later. The inter-view merge candidate derivation unit 381 identifies the corresponding prediction unit of the prediction unit to be processed using the derived disparity vector mvDisp (Sb3). The inter-view merge candidate derivation unit 381 determines whether or not there is a motion vector in the corresponding prediction unit (Sb4). When there is a motion vector (Sb4-Yes), the inter-view merge candidate derivation unit 381 stores the motion vector as an extended merge candidate in the merge candidate storage unit 373 (Sb5), and ends the process. On the other hand, when it is determined in step Sb4 that there is no motion vector (Sb4-No), the inter-view merge candidate derivation unit 381 uses the disparity vector mvDisp acquired in step Sb1 as an extended merge candidate, and a merge candidate storage unit The data is stored in 373 (Sb6), and the process ends.

FIG. 15 is a flowchart for explaining the processing in step Sb1 of FIG. The disparity vector deriving unit 382 includes adjacent prediction units A ₁ , B ₁ , B ₀ , A ₀ , B ₂ of a processing target block, for example, a processing unit prediction unit or a coding unit including the processing target prediction unit. In this order, the processes from Step Sc2 to Step Sc6 are performed (Sc1, Sc7). In step Sc2, the disparity vector deriving unit 382 determines whether or not availableDV indicating that the disparity vector mvDisp is available is false. When availableDV is true (step Sc2-No), the process proceeds to step Sc7, the next adjacent prediction unit is set as a target, and the process returns to step Sc2. On the other hand, when availableDV is false (step Sc2-Yes), the process proceeds to step Sc3, and the disparity vector deriving unit 382 acquires the prediction parameter of the target adjacent prediction unit from the prediction parameter memory 362. Next, the disparity vector deriving unit 382 determines whether or not the vector mvLX that is a disparity vector exists in the target adjacent prediction unit (Sc4). When there is a vector mvLX that is a disparity vector (Sc4-Yes), the process proceeds to step Sc5, and the disparity vector deriving unit 382 sets the vector mvLX as the derived disparity vector mvDisp (Sc5), and availableDV is true. (Step Sc6). On the other hand, when it is determined in step Sc3 that there is no disparity vector (Sc4-No), the process proceeds to step Sc7, the next adjacent prediction unit is set as a target, and the process returns to step Sc2.

  After performing the processing from step Sc2 to step Sc6 for all adjacent prediction units, the process proceeds to step Sc8, and the disparity vector deriving unit 382 determines whether availableDV is false. When availableDV is false (step Sc8-Yes), the process proceeds to step Sc9, the spare disparity vector mvDDV is set as the disparity vector mvDisp, availableDV is set to true (step Sc10), and the process ends. On the other hand, when availableDV is true (step Sc8-No), the process proceeds to step Sc11, and the spare parallax vector setting unit 387 stores the parallax vector mvDisp as the spare parallax vector mvDDV in the prediction parameter memory 362 (Sc6). Exit.

  As described above, the disparity vector deriving unit 382 in the present embodiment sets the zero vector in the coding tree block of the luminance signal at the head of the coding tree unit row as the spare disparity vector mvDDV, thereby performing parallel decoding by WPP. Thus, it is possible to achieve both extended merge candidate derivation processing using the preliminary disparity vector mvDDV.

  FIG. 16 is a schematic block diagram illustrating a configuration of the image encoding device 100. The image encoding device 100 includes a subtraction unit 101, a DCT transform / quantization unit 102, an entropy encoding unit 103, an inverse quantization / inverse DCT transform unit 302, an addition unit 104, a predicted image generation unit 305, a reference image memory 306, A prediction parameter determination unit 105 and a prediction parameter encoding unit 106 are included. The prediction parameter encoding unit 106 includes an inter prediction parameter encoding unit 161 and an intra prediction parameter encoding unit 162. The inverse quantization / inverse DCT transform unit 302, the predicted image generation unit 305, and the reference image memory 306 are the same as the inverse quantization / inverse DCT transform unit 302, the predicted image generation unit 305, and the reference image memory 306 in FIG. The description is omitted.

  The subtraction unit 101 calculates a difference between each picture of the viewpoint image T and the predicted image P generated by the predicted image generation unit 305, and inputs the difference to the DCT transform / quantization unit 102 as a residual signal. The DCT transform / quantization unit 102 performs DCT transform on the residual signal and calculates DCT coefficients. The DCT transform / quantization unit 102 quantizes the calculated DCT coefficient, calculates the quantized coefficient, and inputs the quantized coefficient to the entropy coding unit 103 and the inverse quantization / inverse DCT transform unit 302.

  The entropy encoding unit 103 is a quantization coefficient calculated by the DCT transform / quantization unit 102, a transmission prediction parameter generated by the prediction parameter encoding unit 106, and entropy encoding synchronization input from the outside of the image encoding device 100. A flag entropy_coding_sync_enabled_flag or the like is entropy encoded to generate an encoded stream Te. The entropy encoding unit 103 calculates the code amount (for example, the number of bytes per picture) of the encoded stream Te that has been entropy encoded, and inputs the code amount to the prediction parameter determination unit 105. The addition unit 104 adds the difference image generated by the inverse quantization / DCT conversion unit 302 and the predicted image P generated by the predicted image generation unit 305 to generate a reference image and stores it in the reference image memory 306. .

  The prediction parameter determination unit 105 determines the transmission prediction parameter tp and inputs it to the prediction parameter encoding unit 106 and the entropy encoding unit 103. For example, the prediction parameter determination unit 105 tries with various values of the transmission prediction parameter tp, and sets the value with the smallest code amount of the encoded stream Te calculated by the entropy encoding unit 103 as the transmission prediction parameter tp.

  The inter prediction parameter encoding unit 161 has the same configuration as the inter prediction parameter decoding unit 341 in FIG. The intra prediction parameter encoding unit 162 has the same configuration as the intra prediction parameter decoding unit 342 of FIG.

  For this reason, also in the image coding apparatus 100, when the coding tree unit to be processed is the coding tree block of the first luminance value in the coding tree unit row, the zero vector is set as the preliminary parallax vector mvDDV. , WPP parallel encoding and extended merge candidate derivation processing using the preliminary disparity vector mvDDV can be made compatible.

[Second Embodiment]
The second embodiment of the present invention will be described below with reference to the drawings. The image transmission system 10a according to the present embodiment has the same configuration as that of the image transmission system 10 in FIG. 1, but instead of the image encoding device 100 and the image decoding device 300, an image encoding device 100a and an image decoding device 300a are used. The only difference is that it has. The image encoding device 100a and the image decoding device 300a are different in that they include a merge prediction parameter deriving unit 344a instead of the merge prediction parameter deriving unit 344.

  The merge prediction parameter deriving unit 344a in the present embodiment is not the zero vector as the initial value of the preliminary parallax vector mvDDV, but the coding tree on one row of the coding tree unit to be processed, with respect to the merge prediction parameter deriving unit 344. The difference is that a retained disparity vector mvDDVWpp, which is a preliminary disparity vector derived in the unit row processing, is used. As a result, when the preliminary disparity vector mvDDV is initialized at the head of each coding tree unit row, a more appropriate disparity vector than the zero vector is set as the initial value of the preliminary disparity vector mvDDV, thereby improving the encoding efficiency. The effect of doing.

  FIG. 17 is a schematic block diagram illustrating a configuration of the merge prediction parameter deriving unit 344a. The merge prediction parameter deriving unit 344a is different from the merge prediction parameter deriving unit 344 of FIG. 6 in that an extended merge candidate deriving unit 375a is provided instead of the extended merge candidate deriving unit 375. The extended merge candidate derivation unit 375a is different from the extended merge candidate derivation unit 375 only in that a disparity vector derivation unit 382a is provided instead of the disparity vector derivation unit 382. The disparity vector deriving unit 382a differs from the disparity vector deriving unit 382 in that it has a spare disparity vector setting unit 387a and a spare disparity vector storage unit 388a instead of the spare disparity vector setting unit 387 and the spare disparity vector storage unit 388. .

  The spare disparity vector setting unit 387a is such that the entropy coding synchronization flag entropy_coding_sync_enabled_flag is true, and the coding tree unit to be processed is the coding tree block of the luminance value of the first coding tree unit in the coding tree unit row. In this case, the retained disparity vector mvDDVWpp of the encoded tree unit row on the first row read from the spare disparity vector storage unit 388a is set as the spare disparity vector mvDDV. Also, the spare disparity vector setting unit 387a, when the coding tree unit to be processed is the second coding tree unit in the coding tree unit row and the entropy coding synchronization flag entropy_coding_sync_enabled_flag is true The spare disparity vector storage unit 388a sets the spare disparity vector mvDDV at the time when the processing of the coding tree unit is completed (when the processing of the third coding tree unit in the coding tree unit row is started) as the retained disparity vector mvDDVWpp. Remember me. Note that the preliminary parallax vector mvDDV that the preliminary parallax vector setting unit 387a stores as the retained parallax vector mvDDVWpp is the time when the processing of the first coding tree unit in the coding tree unit row is completed (the second in the coding tree unit row). May be the preliminary disparity vector mvDDV at the time when the processing of the coding tree unit is started.

  FIG. 18 is a flowchart for describing processing in the merge prediction parameter deriving unit 344a. Steps Sz1, Sz2, Sz4, and Sz5 are the same as in FIG. In step Sz3 ′, the backup parallax vector setting unit 387a reads the stored parallax vector mvDDVWpp of the coding tree unit row on the first row of the target coding tree unit from the backup parallax vector storage unit 388a and sets it as the backup parallax vector mvDDV. Then, the process proceeds to step Sz4. However, if the target coding tree unit is included in the coding tree unit row at the top of the picture, a zero vector is set as the preliminary disparity vector mvDDV. The spare disparity vector setting unit 387a is the step when the coding tree unit to be processed is the second coding tree unit in the coding tree unit row and the entropy coding synchronization flag entropy_coding_sync_enabled_flag is true (step Sz6-Yes), the preliminary parallax vector mvDDV is stored in the preliminary parallax vector storage unit 388a as the retained parallax vector mvDDVWpp (step Sz7), and the process proceeds to step Sz5.

  Note that the processing from step Sz6 to step Sz7 for storing the preliminary parallax vector mvDDV in the retained parallax vector mvDDVWpp may be performed before step Sz4 indicating the CTU processing. In this case, the determination in step Sz6 is performed when the encoding tree unit to be processed is the third encoding tree unit in the encoding tree unit row and the entropy encoding synchronization flag entropy_coding_sync_enabled_flag is true. To do.

  As described above, in the present embodiment, when the disparity vector deriving unit 382 derives the disparity vector mvDisp, the preliminary disparity vector mvDDV is initialized with the preliminary disparity of the coding tree unit row on one row instead of the zero vector. By using the holding parallax vector mvDDVsave, which is a vector, an appropriate parallax vector is set as the initial value of the preliminary parallax vector, so that the coding efficiency is improved.

[Third Embodiment]
The third embodiment of the present invention will be described below with reference to the drawings. The image transmission system 10b according to the present embodiment has the same configuration as that of the image transmission system 10 in FIG. 1, but instead of the image encoding device 100 and the image decoding device 300, an image encoding device 100b and an image decoding device 300b are used. The only difference is that it has.

  In the image decoding apparatus 300b according to the present embodiment, it is possible to execute a process called parallel merging that derives in parallel merge candidates of blocks (prediction units and coding units) encoded by merging within a specific region. FIG. 19 is a conceptual diagram for explaining parallel merging. In FIG. 19, block 1 block 1 to block 4 block 4 indicate blocks included in the parallel merge area MER. The parallel merge area MER is a square area in which the size of one side is specified by the parallel merge level Log2ParMrgLevel. To be precise, the size of one side is a square of the parallel merge level Log2ParMrgLevel having a size of 2. Since the parallel merge level Log2ParMrgLevel takes a value of 2 or more and 6 or less, the size of the parallel merge area MER is 4 × 4, 8 × 8, 16 × 16, 32 × 32, and 64 × 64. When the size of the parallel merge area MER is 64 × 64, the coordinates of the parallel merge area MER are the same as those of the coding tree unit.

  In order to perform parallel processing of parallel block merge candidate derivation processing included in the parallel merge region MER (parallel merge), when deriving spatial merge candidates of blocks included in the parallel merge region MER, There is a restriction that prediction parameters in the same parallel merge region MER must not be referred to. For example, when deriving a spatial merge candidate of block 4 block 4, prediction parameters of block 1 block 1 to block 3 block 3 existing in the same parallel merge region MER cannot be referred to. If the coordinates of the block to be processed are (xPb, yPb) and the coordinates of the adjacent block to be referred to when the spatial merge candidate is derived are (xNb, yNb), are both blocks within the same parallel merge area MER? Whether or not it is determined by the following (formula-A1).

(xPb >> Log2ParMrgLevel) == (xNb >> Log2ParMrgLevel) && (yPb >> Log2ParMrgLevel) == (yNb >> Log2ParMrgLevel) (Formula-A1)
When the above determination formula is true, that is, when both blocks exist in the same parallel merge region MER, the prediction parameter of the adjacent block is not referred to.

  An image decoding device 300b illustrated in FIG. 20 has the same configuration as that of the image decoding device 300 in FIG. 4, except that the prediction parameter decoding unit 304b is replaced with the entropy decoding unit 301 instead of the prediction parameter decoding unit 304, and the entropy. The difference is that the decoding unit 301b is provided. The image encoding device 100b has the same configuration as that of the image encoding device 100 in FIG. 16, but instead of the prediction parameter encoding unit 106, the prediction parameter encoding unit 106b is replaced with the entropy encoding unit 103. The difference is that an entropy encoding unit 103b is provided. The entropy encoding unit 103b also sets the parallel merge level Log2ParMrgLevel input from the outside of the image encoding device 100b as a target of entropy encoding.

  The prediction parameter decoding unit 304b has the same configuration as the prediction parameter decoding unit 304 in FIG. 4 except that an inter prediction parameter decoding unit 341b is provided instead of the inter prediction parameter decoding unit 341. The prediction parameter decoding unit 304b has the same configuration as the prediction parameter decoding unit 304 in FIG. 4 except that an inter prediction parameter decoding unit 341b is provided instead of the inter prediction parameter decoding unit 341. The inter prediction parameter decoding unit 341b has the same configuration as the inter prediction parameter decoding unit 341b. The inter prediction parameter decoding unit 341b has the same configuration as the inter prediction parameter decoding unit 341 in FIG. 5 except that a merge prediction parameter derivation unit 344b is provided instead of the merge prediction parameter derivation unit 344.

  The merge prediction parameter derivation unit 344b according to the present embodiment uses the spare disparity vector mvDDV when the parallel merge level Log2ParMrgLevel is larger than 2, that is, when the parallel merge can be executed, with respect to the merge prediction parameter derivation unit 344. The difference is not. As a result, the dependency between blocks in the parallel merge region, which has occurred by using the preliminary disparity vector mvDDV updated every time the block is decoded, is eliminated, and the extended merge candidate derivation process is used in combination with the parallel merge. There is an effect that becomes possible.

  Returning to FIG. 20, the entropy decoding unit 301b and the entropy decoding unit 301 entropy-decode the encoded stream Te, and use the parallel merge level Log2ParMrgLevel indicating the size of the parallel merge region obtained by entropy decoding as the inter prediction parameter decoding unit. The difference is that it is input to 341b.

  FIG. 21 is a schematic block diagram illustrating a configuration of the merge prediction parameter deriving unit 344b. The merge prediction parameter deriving unit 344b is different in that it includes a disparity vector deriving unit 382b instead of the disparity vector deriving unit 382 and a spatial merge candidate deriving unit 383b instead of the spatial merge candidate deriving unit 383.

  The spatial merge candidate derivation unit 383b does not refer to the prediction parameter of the adjacent block when the adjacent block is included in the same parallel merge area as the processing target block.

  The disparity vector derivation unit 382b uses the preliminary disparity vector mvDDV only when the parallel merge level Log2ParMrgLevel is 2, that is, when the size of the parallel merge area is 4 × 4 and the parallel merge cannot be executed.

  FIG. 22 is a flowchart for explaining processing in the merge prediction parameter deriving unit 344b. Step Sa1, Step Sa2, and Step Sa5 to Step Sa15 are the same as those in FIG.

  In step Sa4 ′, the spatial merge candidate derivation unit 383b derives a spatial merge candidate by the same method as the spatial merge candidate derivation unit 383. However, adjacent PUs included in the same parallel merge area as the target block are not referred to. In other words, if the coordinates of the target block are (xPb, yPb) and the coordinates of the adjacent block are (xNb, yNb), the coordinates when the coordinates of the target block and the coordinates of the adjacent block are right-shifted by Log2ParMrgLevel must match. (Expression-A1) is established, the availability of adjacent blocks (availableN) is set to false and is not referred to.

  FIG. 23 is a flowchart for explaining the processing in step Sa3 ′ of FIG. Steps Sb3 to Sb6 are the same as in FIG.

  FIG. 24 is a flowchart illustrating the process in step Se1 ′ of FIG. Steps Sc1 to Sc3 and Steps Sc5 to Sc11 are the same as in FIG. In step Sc4 ′, the disparity vector deriving unit 382 determines whether or not the adjacent prediction unit belongs to a parallel merge region different from the processing target block and the adjacent prediction unit includes the vector mvLX that is a disparity vector. If the condition is satisfied and the condition is satisfied (Sc3′-Yes), the process proceeds to Step Sc5. If the condition is not satisfied (Sc3′-No), the process proceeds to Step Sc7. In step Sc12, the disparity vector deriving unit 382 determines whether or not the parallel merge level Log2ParMrgLevel is 2. If the parallel merge level Log2ParMrgLevel is 2 (step Sc12-Yes), the process proceeds to step Sc8. If the parallel merge level Log2ParMrgLevel is not 2 (step Sc12-No), the process is terminated.

  As described above, the disparity vector deriving unit 382b in the present embodiment processes the extended merge candidate derivation process in parallel by not using the preliminary disparity vector mvDDV as the disparity vector mvDisp when the parallel merge level Log2ParMrgLevel is greater than 2. It is possible to achieve the effect (parallel merging is possible).

[Fourth Embodiment]
Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. The image transmission system 10c according to the present embodiment has the same configuration as that of the image transmission system 10 in FIG. 1 except that the image encoding device 100c and the image decoding device 300c are replaced with the image encoding device 100 and the image decoding device 300. The only difference is that it has.

  The image decoding device 300c has the same configuration as that of the image decoding device 300b in FIG. 20, except that a prediction parameter decoding unit 304c is provided instead of the prediction parameter decoding unit 304b. Similar to the image decoding device 300b, the image decoding device 300c can perform parallel merging in which merge candidates of blocks encoded by merging in a specific region are derived in parallel. The image encoding device 100c has the same configuration as that of the image encoding device 100b, except that a prediction parameter encoding unit 106c is provided instead of the prediction parameter encoding unit 106b.

  The prediction parameter decoding unit 304c has the same configuration as the prediction parameter decoding unit 304b of FIG. 20, except that an inter prediction parameter decoding unit 341c is provided instead of the inter prediction parameter decoding unit 341b. The prediction parameter decoding unit 304c has the same configuration as the prediction parameter decoding unit 304b, except that an inter prediction parameter decoding unit 341c is provided instead of the inter prediction parameter decoding unit 341b. The inter prediction parameter decoding unit 341c has the same configuration as the inter prediction parameter decoding unit 341c. The inter prediction parameter decoding unit 341c has the same configuration as the inter prediction parameter decoding unit 341b, but differs in that it includes a merge prediction parameter derivation unit 344c instead of the merge prediction parameter derivation unit 344b.

  The merge prediction parameter derivation unit 344c in the present embodiment starts the decoding process of the first block in the parallel merge region specified by the parallel merge level Log2ParMrgLevel, with respect to the merge prediction parameter derivation unit 344, to update the preliminary disparity vector mvDDV. The point that is done at the time is different. As a result, the spare disparity vector mvDDV does not change in the parallel merge region, and there is no dependency on the spare disparity vector mvDDV between the blocks in the parallel merge region. This can be executed during merging, and the encoding efficiency is improved.

  The merge prediction parameter deriving unit 344c has the same configuration as the merge prediction parameter deriving unit 344b of FIG. 21, except that a disparity vector deriving unit 382c is provided instead of the disparity vector deriving unit 382b. The disparity vector deriving unit 382c has the same configuration as the disparity vector deriving unit 382b of FIG. 21, but the disparity vector setting unit 387c is replaced with the disparity vector setting unit 387b, and the disparity vector storage unit 388b is replaced with the disparity vector storage unit 388b. The difference is that it has 388c.

  The disparity vector setting unit 387c, when the target block is the first block in the parallel merge area specified by the parallel merge level Log2ParMrgLevel, that is, when the coordinates of the target block coincide with the coordinates of the parallel merge area, The stored parallax vector mvDDVsave is read from the preliminary parallax vector storage unit 388c and set as the preliminary parallax vector mvDDV. When the coordinates of the target block are (xPb, yPb), the disparity vector setting unit 387c determines whether or not the target block is the first block in the parallel merge region using (Equation -B1) below.

(xPb% (2 << Log2ParMrgLevel)) == 0 && (yPb% (2 << Log2ParMrgLevel)) == 0 (Formula -B1)
When the above determination formula is true, that is, when the target block is the first block in the parallel merge region, the retained parallax vector mvDDVsave is read from the spare parallax vector storage unit 388c and set as the spare parallax vector mvDDV.

  Further, the disparity vector setting unit 387c outputs the derived disparity vector mvDisp to the disparity vector storage unit 388c as the retained disparity vector mvDDVsave.

  FIG. 25 is a flowchart for describing processing in the merge prediction parameter deriving unit 344c. The merge prediction parameter deriving unit 344c performs the processing from step Sz2 ′ to Sz4 ′ on each parallel merge region with the step Sz1 ′ and step Sz5 ′ as a parallel merge region loop (step Sz1 ′, step Sz5 ′). . If the target block is the first block in the parallel merge area specified by the parallel merge level Log2ParMrgLevel (Sz2′-Yes), the disparity vector deriving unit 382c obtains the retained disparity vector mvDDVsave from the spare disparity vector storage unit. Read and set as a preliminary parallax vector mvDisp (Sz3 ′).

  Next, the merge prediction parameter deriving unit 344c derives merge candidates for each prediction unit PU in each coding unit CU included in the parallel merge region (step Sz4 ′). Since the derivation method is the same as the flow in FIG. 22 except that step Sa3 ′ is replaced by step Sa3 ″, detailed description is omitted.

  The processing of step Sa3 ″ is the same as the flow of FIG. 23 except that step Se1 ′ is replaced by step Se1 ″, and detailed description thereof is omitted.

  Note that the processing from step Sz2 ′ to step Sz3 for setting the retained parallax vector mvDDVsave as the preliminary parallax vector mvDDV may be performed after step Sz4 indicating the CU processing. In this case, the determination in step Sz2 ′ is performed when the target block is the last block in the parallel merge area specified by the parallel merge level Log2ParMrgLevel. When the coordinate of the target block is (xPb, yPb), the horizontal width is nPbW, and the height is nPbH, the disparity vector setting unit 387c determines whether the target block is the last block in the parallel merge region ( The determination is made using equation -B2).

((xPb + nPbW)% (2 << Log2ParMrgLevel)) == 0 && ((yPb + nPbH)% (2 << Log2ParMrgLevel)) == 0 (Formula -B2)
When the above determination formula is true, that is, when the target block is the last block in the parallel merge area, the retained parallax vector mvDDVsave is read from the spare parallax vector storage unit 388c and set as the spare parallax vector mvDDV.

  FIG. 26 is a flowchart for explaining the operation of step Se1 ″. Of the steps in FIG. 26, steps other than step Sc11 ′ are the same as in FIG. In step Sc11 ′, the disparity vector setting unit 387c outputs the disparity vector mvDisp to the disparity vector storage unit 388c, stores it as the retained disparity vector mvDDVsave, and ends the process.

  As described above, the disparity vector deriving unit 382c in the present embodiment performs the update of the preliminary disparity vector mvDDV at the start of the decoding process of the first block in the parallel merge area specified by the parallel merge level Log2ParMrgLevel. As a result, the preliminary disparity vector mvDDV does not change in the parallel merge region, and there is no dependency between blocks in the parallel merge region, so the extended merge candidate derivation process using the preliminary disparity vector mvDDV is executed during the parallel merge. It becomes possible.

  In addition, a computer-readable program for realizing the functions of each of the image encoding devices 100, 100a, 100b, and 100c, and the image decoding devices 300, 300a, 300b, and 300c in each of the above-described embodiments, or a part of each function. Each apparatus may be realized by recording on a recording medium, causing the computer system to read and execute a program recorded on the recording medium. Here, the “computer system” includes an OS and hardware such as peripheral devices.

  Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.

  The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  In addition, part or all of the image encoding devices 100, 100a, 100b, and 100c and the image decoding devices 300, 300a, 300b, and 300c in the above-described embodiments are typically realized as an LSI that is an integrated circuit. May be. Each functional block of the image encoding devices 100, 100a, 100b, 100c and the image decoding devices 300, 300a, 300b, 300c may be individually chipped, or a part or all of them may be integrated into a chip. . Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integrated circuit technology that replaces LSI appears due to the advancement of semiconductor technology, an integrated circuit based on the technology can be used.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes and the like within a scope not departing from the gist of the present invention are included. .

DESCRIPTION OF SYMBOLS 10 ... Image transmission system 100, 100a, 100b, 100c ... Image coding apparatus 101 ... Subtraction part 102 ... DCT conversion / quantization part 103 ... Entropy coding part 104 ... Addition part 105 ... Prediction parameter determination part 106 ... Prediction parameter code 200: network 300, 300a, 300b, 300c ... image decoding device 301, 301b ... entropy decoding unit 302 ... inverse quantization / inverse DCT transform unit 303 ... addition unit 304, 304b, 304c ... prediction parameter decoding unit 305 ... prediction Image generation unit 306 ... Reference image memory 341, 341b, 341c ... Inter prediction parameter decoding unit 342 ... Intra prediction parameter decoding unit 343 ... Inter prediction parameter extraction unit 344, 344a, 344b, 344c ... Merge prediction parameter derivation unit 45 ... AMVP prediction parameter derivation unit 346 ... addition unit 347 ... vector candidate derivation unit 348 ... prediction vector selection unit 351 ... inter prediction image generation unit 352 ... intra prediction image generation unit 361 ... image memory 362, 362a ... prediction parameter memory 371 ... Merge candidate derivation unit 372 ... Merge candidate selection unit 373 ... Merge candidate storage unit 374 ... Merge candidate derivation control unit 375, 375b ... Extended merge candidate derivation unit 376 ... Basic merge candidate derivation unit 381 ... Interview merge candidate derivation unit 382, 382a , 382b, 382c ... disparity vector deriving unit 383, 383b ... spatial merge candidate deriving unit 384 ... temporal merge candidate deriving unit 385 ... combined merge candidate deriving unit 386 ... zero merge candidate deriving unit 387, 387a, 387b, 387c ... preliminary disparity vector Tough 388,388a, 388b, 388c ... preliminary disparity vector storage unit 400 ... image display device

Claims (13)

An image decoding device that decodes an image in units of a coding tree block of a predetermined size,
An entropy decoding unit that decodes syntax elements from the encoded data;
A disparity vector deriving unit for deriving a disparity vector from an adjacent vector or a preliminary disparity vector that is a vector of a block adjacent to the target block;
The entropy decoding unit decodes the entropy encoding synchronization flag. When the entropy encoding synchronization flag is 1, CABAC decoding processing is performed at the start of decoding of the first luminance encoding tree block in the encoding tree unit row. Initialize the
The disparity vector deriving unit sets the adjacent vector as the disparity vector of the target block when the adjacent vector is available, and sets the preliminary disparity vector as the disparity vector when the adjacent vector is not available. Means to set as
Means for setting the neighboring vector as the preliminary disparity vector when the neighboring vector is available;
When the entropy coding synchronization flag is 1, the disparity vector derivation unit initializes the preliminary disparity vector at the start of decoding of the first luminance coding tree block in the coding tree unit row, and An image decoding apparatus comprising: a preliminary parallax vector setting unit that sets a parallax vector as the preliminary parallax vector when a block is available.   2. The image decoding device according to claim 1, wherein the preliminary parallax vector setting unit initializes the preliminary parallax vector as a zero vector.   2. The image decoding according to claim 1, wherein the spare disparity vector setting unit initializes the spare disparity vector with a spare disparity vector of a decoded coding tree block in a coding tree block row one level higher. apparatus.   The image according to claim 3, wherein the spare vector setting unit initializes the spare disparity vector with the spare disparity vector of the second decoded encoded tree block in the next higher encoded tree block row. Decoding device. An image decoding device that decodes an image in units of a coding tree block of a predetermined size,
An entropy decoding unit that decodes syntax elements from the encoded data;
A disparity vector deriving unit for deriving a disparity vector from a vector of a block adjacent to the target block or a preliminary disparity vector;
The entropy decoding unit decodes a parallel merge level;
The disparity vector derivation unit includes means for determining availability of the vector of the adjacent block according to the parallel merge level and the coordinates of the block adjacent to the target block,
Further, the disparity vector setting unit changes a method for deriving a preliminary disparity vector according to the value of the parallel merge level.   The image decoding apparatus according to claim 5, wherein the disparity vector setting unit uses a preliminary disparity vector as a disparity vector of the target block only when the parallel merge level is 2.   The disparity vector setting unit updates the spare disparity vector at the time of decoding the first block of the parallel merge region when the image is divided in parallel merge region units that are regions of a predetermined size determined by the parallel merge level. The image decoding device according to claim 5, wherein:   When the disparity vector setting unit divides the image into parallel merge region units that are regions of a predetermined size determined by the parallel merge level, the disparity vector setting unit is preceded by the time when the coordinates of the target block coincide with the coordinates of the parallel merge region. The image decoding apparatus according to claim 7, wherein the adjacent vector derived as a disparity vector in a block to be set is set as a preliminary disparity vector.   An image coding apparatus comprising the disparity vector setting unit according to any one of claims 1 to 8. An image decoding method for decoding an image in units of a coding tree block of a predetermined size,
A first step of decoding syntax elements from the encoded data;
A second step of deriving a disparity vector from an adjacent vector or a preliminary disparity vector that is a vector of a block adjacent to the target block;
In the first step, the entropy coding synchronization flag is decoded. When the entropy coding synchronization flag is 1, CABAC decoding is performed at the decoding start time of the first luminance coding tree block in the coding tree unit row. Initialize the process,
In the second step, when the adjacent vector is available, the adjacent vector is set as the disparity vector of the target block, and when the adjacent vector is not available, the preliminary disparity vector is set as the disparity vector. Set as
If the neighboring vector is available, set the neighboring vector as the preliminary disparity vector;
When the entropy coding synchronization flag is 1, the preliminary disparity vector is initialized at the start of decoding of the first luminance coding tree block in the coding tree unit row, and the adjacent block is available Is a method for decoding an image, wherein a disparity vector is set as the preliminary disparity vector. An image decoding method for decoding an image in units of a coding tree block of a predetermined size,
A first step of decoding syntax elements from the encoded data;
A second step of deriving a disparity vector from a vector of a block adjacent to the target block or a preliminary disparity vector;
Decoding the parallel merge level in the first step;
In the second step, the availability of the vector of the adjacent block is determined according to the parallel merge level and the coordinates of the block adjacent to the target block,
Further, the disparity vector setting unit changes a method for deriving a preliminary disparity vector according to the value of the parallel merge level. Computer
A program for functioning as an image decoding device that decodes an image in units of a coding tree block of a predetermined size,
The image decoding device includes:
An entropy decoding unit that decodes syntax elements from the encoded data;
A disparity vector deriving unit for deriving a disparity vector from an adjacent vector or a preliminary disparity vector that is a vector of a block adjacent to the target block;
The entropy decoding unit decodes the entropy encoding synchronization flag. When the entropy encoding synchronization flag is 1, CABAC decoding processing is performed at the start of decoding of the first luminance encoding tree block in the encoding tree unit row. Initialize the
The disparity vector deriving unit sets the adjacent vector as the disparity vector of the target block when the adjacent vector is available, and sets the preliminary disparity vector as the disparity vector when the adjacent vector is not available. Means to set as
Means for setting the neighboring vector as the preliminary disparity vector when the neighboring vector is available;
When the entropy coding synchronization flag is 1, the disparity vector derivation unit initializes the preliminary disparity vector at the start of decoding of the first luminance coding tree block in the coding tree unit row, and A program comprising: a preliminary parallax vector setting unit that sets a parallax vector as the preliminary parallax vector when a block is available. Computer
A program for functioning as an image decoding device that decodes an image in units of a coding tree block of a predetermined size,
The image decoding device includes:
An entropy decoding unit that decodes syntax elements from the encoded data;
A disparity vector deriving unit for deriving a disparity vector from a vector of a block adjacent to the target block or a preliminary disparity vector;
The entropy decoding unit decodes a parallel merge level;
The disparity vector derivation unit includes means for determining availability of the vector of the adjacent block according to the parallel merge level and the coordinates of the block adjacent to the target block,
Furthermore, the disparity vector setting unit changes a method for deriving a preliminary disparity vector according to the value of the parallel merge level.