Intra-prediction device, encoding device, decoding device, and program

Abstract

To improve coding efficiency by curved intra-prediction while restraining an increase in processing complexity.SOLUTION: An intra-prediction device for performing intra-prediction every block constituting an image includes a determination unit for determining a second prediction mode indicating a final prediction direction when the prediction direction is gradually changed for each sub-region in a case where a target block to which a first prediction mode having a linear prediction direction is assigned is divided into a plurality of sub-regions, an assignment unit for assigning a sub-prediction mode to each sub-region according to a predetermined rule such that the prediction direction is gradually changed for each sub-region toward the prediction direction of the second prediction mode based on the prediction direction of the first prediction mode, and a prediction unit for predicting each sub-region by the intra prediction using the corresponding sub-prediction mode.SELECTED DRAWING: Figure 1

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