Intra prediction method and apparatus, and image encoding/decoding method and apparatus using same
A video decoding method using an intra prediction, includes: predicting a current block from a plurality of neighboring blocks of the current block; decoding a bitstream to thereby extract residual signals; inversely quantizing the residual signals; inversely transforming the inversely quantized residual signals; and adding the inversely transformed residual signals to the predicted pixels in the predicted block, wherein the prediction of the current block comprises: calculating a plurality of weighted pixel values of pixels selected in the neighboring blocks by applying weights to the pixels selected in the neighboring blocks, wherein the weights are decided variably based on a position of a current pixel to be predicted in the current block; and deriving a predicted pixel value of the current pixel using the weighted pixel values.
1. A video decoding method using an intra prediction, the method comprising:
predicting a current block from a plurality of neighboring blocks of the current block;
decoding a bitstream to thereby extract residual signals;
inversely quantizing the residual signals;
inversely transforming the inversely quantized residual signals; and
adding the inversely transformed residual signals to the predicted pixels in the predicted block,
wherein the prediction of the current block comprises:
calculating a plurality of weighted pixel values of pixels selected in the neighboring blocks by applying weights to the pixels selected in the neighboring blocks, wherein the weights are decided variably based on a position of a current pixel to be predicted in the current block; and
deriving a predicted pixel value of the current pixel using the weighted pixel values,
wherein the pixels selected in the neighboring blocks comprise:
a first pixel which is included in an upper neighboring block and located at the same column with the current pixel, and
a second pixel which is included in a left neighboring block and located at the same row with the current pixel.
2. The method of claim 1 , wherein the weighted pixel values comprise:
a first weighted pixel value calculated by applying a first weight of the weights to the first pixel in the upper neighboring block, and
a second weighted pixel value calculated by applying a second weight of the weights to the second pixel in the left neighboring block.
3. The method of claim 2 , wherein the first weight is decided by the distance between the current pixel and the first pixel in the upper neighboring block, and the second weight is decided by the distance between the current pixel and the second pixel in the left neighboring block.
4. The method of claim 1 , wherein the weights are decided by the distance between the current pixel and each of the pixels selected in the neighboring blocks.
5. The method of claim 1 , wherein a greater weight is applied to a pixel having a shorter distance from the current pixel among the pixels selected in the neighboring blocks.
6. The method of claim 1 , wherein the predicted pixel value of the current pixel is derived by dividing a sum of the weighted pixel values by a sum of the weights.
7. The method of claim 1 , wherein the weighted pixel values further comprise one or more third weighted pixel values calculated by applying third weights of the weights to one or more third pixels in the neighboring blocks.
8. The method of claim 1 , wherein the weighted pixel values further comprise:
a third weighted pixel value calculated by applying a third weight of the weights to a third pixel located at an upper outside of the current block, and
a fourth weighted pixel value calculated by applying a fourth weight of the weights to a fourth pixel located at an left outside of the current block.