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JP-7854606-B2 - Image encoding device and image encoding method, and image decoding device and image decoding method

JP7854606B2JP 7854606 B2JP7854606 B2JP 7854606B2JP-7854606-B2

Inventors

  • 福島 茂
  • 中村 博哉
  • 熊倉 徹

Assignees

  • 合同会社ＩＰ Ｂｒｉｄｇｅ１号

Dates

Publication Date
20260507
Application Date
20250521

Claims (6)

  1. An image encoding device that divides an image into blocks, encodes each divided block, and generates a bitstream, A luminance signal block division unit that divides the luminance signal of an image into rectangles to generate luminance signal blocks, A color difference signal block division unit divides the color difference signals of an image into rectangles to generate color difference signal blocks, A luminance signal prediction unit that predicts the luminance signal, It includes a color difference signal prediction unit that predicts the color difference signal, The aforementioned color difference signal prediction unit is capable of luminance-color difference intra-prediction, which predicts the color difference signal from the decoded luminance signal. The luminance signal block division unit recursively divides the luminance signal of the image into four parts in the horizontal and vertical directions, or recursively divides it into two parts in the horizontal or vertical directions. The color difference signal block division unit recursively divides the color difference signal of the image into four parts in the horizontal and vertical directions, or into two parts in the horizontal or vertical directions. The luminance signal block and the chrominance signal block are separated independently in the case of intra prediction, and if the size of the luminance signal block is greater than or equal to a predetermined size, the luminance chrominance intra prediction is prohibited. In the case of interpretation, the luminance signal block and the chrominance signal block are divided into blocks of the same area . An image coding device characterized by the following:
  2. An image encoding method that divides an image into blocks, encodes each divided block, and generates a bitstream, A luminance signal block division step involves dividing the luminance signal of an image into rectangles to generate luminance signal blocks, and A color difference signal block division step involves dividing the color difference signal of an image into rectangles to generate color difference signal blocks, and A luminance signal prediction step that predicts the luminance signal, This includes a color difference signal prediction step that predicts the color difference signal, In the aforementioned color difference signal prediction step, it is possible to perform luminance-color difference intra-prediction, which predicts the color difference signal from the decoded luminance signal. The image's luminance signal is recursively divided into four parts horizontally and vertically, or into two parts horizontally or vertically. The color difference signal of the image is recursively divided into four parts horizontally and vertically, or into two parts horizontally or vertically. The luminance signal block and the chrominance signal block are separated independently in the case of intra prediction, and if the size of the luminance signal block is greater than or equal to a predetermined size, the luminance chrominance intra prediction is prohibited. In the case of interpretation, the luminance signal block and the chrominance signal block are divided into blocks of the same area . An image encoding method characterized by the following.
  3. An image decoding device that decodes an image in blocks, A luminance signal block division unit that divides the luminance signal of an image into rectangles to generate luminance signal blocks, A color difference signal block division unit divides the color difference signals of an image into rectangles to generate color difference signal blocks, A luminance signal prediction unit that predicts the luminance signal, It includes a color difference signal prediction unit that predicts the color difference signal, The aforementioned color difference signal prediction unit is capable of luminance-color difference intra-prediction, which predicts the color difference signal from the decoded luminance signal. The luminance signal block division unit recursively divides the luminance signal of the image into four parts in the horizontal and vertical directions, or recursively divides it into two parts in the horizontal or vertical directions. The color difference signal block division unit recursively divides the color difference signal of the image into four parts in the horizontal and vertical directions, or into two parts in the horizontal or vertical directions. The luminance signal block and the chrominance signal block are separated independently in the case of intra prediction, and if the size of the luminance signal block is greater than or equal to a predetermined size, the luminance chrominance intra prediction is prohibited. In the case of interpretation, the luminance signal block and the chrominance signal block are divided into blocks of the same area . An image decoding device characterized by the following features.
  4. An image decoding method that decodes an image in units of divided blocks, A luminance signal block division step involves dividing the luminance signal of an image into rectangles to generate luminance signal blocks, and A color difference signal block division step involves dividing the color difference signal of an image into rectangles to generate color difference signal blocks, and A luminance signal prediction step that predicts the luminance signal, This includes a color difference signal prediction step that predicts the color difference signal, In the aforementioned color difference signal prediction step, it is possible to perform luminance-color difference intra-prediction, which predicts the color difference signal from the decoded luminance signal. The image's luminance signal is recursively divided into four parts horizontally and vertically, or into two parts horizontally or vertically. The color difference signal of the image is recursively divided into four parts horizontally and vertically, or into two parts horizontally or vertically. The luminance signal block and the chrominance signal block are separated independently in the case of intra prediction, and if the size of the luminance signal block is greater than or equal to a predetermined size, the luminance chrominance intra prediction is prohibited. In the case of interpretation, the luminance signal block and the chrominance signal block are divided into blocks of the same area . An image decoding method characterized by the following:
  5. A storage method for storing a bitstream generated according to the image encoding method described in claim 2 into a recording medium.
  6. A transmission method for transmitting a bitstream generated according to the image encoding method described in claim 2.

Description

This invention relates to a technique for dividing an image into blocks and performing encoding and decoding on a block-by-block basis. In image coding and decoding, an image is divided into blocks, which are sets of a predetermined number of pixels, and coding and decoding are performed on a block-by-block basis. Appropriate block division improves the coding efficiency of both intra-frame prediction and inter-frame prediction. Furthermore, in intra-frame prediction, coding efficiency is improved by predicting the secondary signal from the decoded image of the primary signal. Japanese Patent Publication No. 2013-90015 This is a configuration diagram of an image encoding device according to the first embodiment.This is a configuration diagram of an image decoding device according to the first embodiment.This is a flowchart illustrating the division into tree blocks and the division within tree blocks.This diagram shows how an input image is divided into tree blocks.This is a diagram explaining the z-scan.This diagram shows a tree block divided into four sections horizontally and vertically.This diagram shows a tree block divided horizontally into two sections.This diagram shows a tree block divided vertically into two sections.This flowchart explains how to process each of the four divided blocks when a tree block is divided horizontally and vertically.This flowchart explains how to process each of the two divided blocks when a tree block is split horizontally into two sections.This diagram shows how a tree block is subdivided when it is divided horizontally into two sections.This flowchart explains how to process each of the two divided blocks when a tree block is split vertically into two.This diagram shows how a tree block is subdivided when it is divided vertically into two sections.This figure shows an example of the syntax for block partitioning in the first embodiment.This diagram illustrates intra-prediction.This is a diagram explaining interpretation prediction.This is a diagram illustrating the color difference format.This diagram illustrates the prediction of luminance chromatic difference intra-prediction.This is a flowchart explaining the luminance chrominance intra prediction.This diagram illustrates the case where the size of the color difference block is larger than the size of the luminance block.This diagram illustrates the case where the size of the color difference block is smaller than the size of the luminance block.This diagram illustrates an example of the syntax for the intra-color difference prediction mode.This diagram illustrates an example of restricting intra-color difference prediction by replacing peripheral pixels.This diagram illustrates the prediction of luminance color difference intra-level due to differences in luminance block size. One embodiment of the present invention provides an image encoding technique that divides an image into rectangular blocks and encodes and decodes the divided blocks. (First Embodiment) An image encoding device 100 and an image decoding device 200 according to Embodiment 1 of the present invention will be described below. Figure 1 is a configuration diagram of the image encoding device 100 according to the first embodiment. Here, Figure 1 only shows the data flow related to the image signal; additional information other than the image signal, such as motion vectors and prediction modes, is supplied by each component to the encoding bit sequence generation unit 105 to generate corresponding encoded data, but the data flow related to this additional information is not shown. The block division unit 101 divides the image into encoding target blocks, which are the processing units for encoding, and supplies the image signals within the encoding target blocks to the residual signal generation unit 103. The block division unit 101 also supplies the image signals from the encoding target blocks to the prediction image generation unit 102 in order to evaluate the degree of agreement with the predicted image. The block division unit 101 recursively divides the image into rectangles of a predetermined size to generate blocks to be encoded. The block division unit 101 includes a four-part division unit that divides the target block in the recursive division horizontally and vertically into four parts to generate four blocks, and a two-part division unit that divides the target block in the recursive division into two parts horizontally or vertically to generate two blocks. The detailed operation of the block division unit 101 will be described later. The prediction image generation unit 102 generates a prediction image signal by performing intra-picture prediction or inter-picture prediction based on the prediction mode from the decoded image signal supplied from the decoded image memory 108. The image signal within the block to be encoded supplied from the block division unit 101 is used to evaluate intra-prediction and inter-prediction. In intra-pred