An image encoding method that generates and encodes a gram matrix representing an image feature when encoding an image to be encoded includes a feature map generation step of generating a plurality of feature maps from the image to be encoded; a gram matrix generation step of generating a gram matrix through calculations between/among the feature maps; a representative vector determination step of generating a representative vector and a representative coefficient value by singular value decomposition of the gram matrix; and a vector encoding step of encoding the representative coefficient value and the representative vector.

An image encoding method that generates and encodes a gram matrix representing an image feature when encoding an image to be encoded includes a feature map generation step of generating a plurality of feature maps from the image to be encoded; a gram matrix generation step of generating a gram matrix through calculations between/among the feature maps; a representative vector determination step of generating a representative vector and a representative coefficient value by singular value decomposition of the gram matrix; and a vector encoding step of encoding the representative coefficient value and the representative vector.

An image encoding method that expresses an image using pixels or blocks, and colors assigned to the pixels or the blocks when encoding an image to be encoded, and encodes a block division tree and color information, the color information being assigned to all nodes including a root node, branch nodes, and leaf nodes of the block division tree, the method includes: a division tree generation step of dividing the image to be encoded using an arbitrary division tree and thereby generating the block division tree; a color information determination step of determining representative colors that represent interim blocks or final blocks and assigning the determined colors as color information corresponding to the respective nodes, the interim blocks or the final blocks corresponding to the nodes of the block division tree; a tree encoding step of encoding the block division tree; and a color information encoding step of encoding the color information.

An encoder includes circuitry and memory coupled to the circuitry. In operation, the circuitry: switches whether to encode a first flag, according to whether a multilayer coding scheme is used to encode one or more pictures, the first flag indicating whether use of one or more interlayer reference pictures for interlayer prediction is allowed.

An encoder includes circuitry and memory coupled to the circuitry. In operation, the circuitry: switches whether to encode a first flag, according to whether a multilayer coding scheme is used to encode one or more pictures, the first flag indicating whether use of one or more interlayer reference pictures for interlayer prediction is allowed.

Disclosed herein is an intra prediction method including: deriving neighbor prediction mode information from a left neighbor prediction mode and an upper neighbor prediction mode; deriving an intra prediction mode for a decoding target unit by using the derived neighbor prediction mode information; and performing intra prediction on the decoding target unit based on the intra prediction mode. According to exemplary embodiments of the present invention, image encoding/decoding efficiency can be improved.

Disclosed herein is an intra prediction method including: deriving neighbor prediction mode information from a left neighbor prediction mode and an upper neighbor prediction mode; deriving an intra prediction mode for a decoding target unit by using the derived neighbor prediction mode information; and performing intra prediction on the decoding target unit based on the intra prediction mode. According to exemplary embodiments of the present invention, image encoding/decoding efficiency can be improved.

Provided is a picture encoding device that divides a picture into blocks and performs encoding for each of the divided blocks. A primary signal block divider divides a primary signal of the picture into rectangles having a predetermined size, and generates a primary signal block. A secondary signal block divider divides a secondary signal of the picture into rectangles having a predetermined size, and generates a secondary signal block. A primary signal predictor predicts a primary signal, and a secondary signal predictor predicts a secondary signal. The secondary signal predictor can perform inter prediction of predicting a secondary signal from an encoded primary signal, and the inter prediction is restricted based on at least one of a size of the primary signal block and a size of the secondary signal block.

Provided is a picture encoding device that divides a picture into blocks and performs encoding for each of the divided blocks. A primary signal block divider divides a primary signal of the picture into rectangles having a predetermined size, and generates a primary signal block. A secondary signal block divider divides a secondary signal of the picture into rectangles having a predetermined size, and generates a secondary signal block. A primary signal predictor predicts a primary signal, and a secondary signal predictor predicts a secondary signal. The secondary signal predictor can perform inter prediction of predicting a secondary signal from an encoded primary signal, and the inter prediction is restricted based on at least one of a size of the primary signal block and a size of the secondary signal block.

An image decoding method performed by a decoding device according to the present disclosure comprises the steps of: receiving a bitstream containing at least one of segmentation information of a current picture and prediction information for a current block included in the current picture; deriving a first segmentation structure of the current picture, which is based on multiple tiles, on the basis of the segmentation information of the current picture including at least one of information of the number of width-parsing columns, information of the last width, information of the number of height-parsing rows, and information of the last height; deriving a block predicted for the current block, on the basis of the prediction information for the current block contained in one of the multiple tiles; and generating reconstruction samples for the current block on the basis of the predicted block.