Intra prediction method and apparatus, and image encoding/decoding method and apparatus using same
A video decoding apparatus using an intra prediction, includes: a decoder to decode a bitstream to thereby extract residual signals; an inverse quantizer to inversely quantize the residual signals; an inverse transformer to inversely transform the inversely quantized residual signals; an intra predictor to predict a current block from a plurality of neighboring blocks of the current block; and an adder to add the inversely transformed residual signals to the predicted pixels in the predicted block, wherein the intra predictor includes a weighted pixel calculator to calculate a plurality of weighted pixel values of pixels selected in the neighboring blocks by applying weights to the pixels selected in the neighboring blocks, the weights being decided variably based on a position of a current pixel to be predicted in the current block; and a pixel predictor to derive a predicted pixel value of the current pixel using the weighted pixel values.
1. A video decoding apparatus using an intra prediction, the apparatus comprising:
a decoder configured to decode a bitstream to thereby extract residual signals;
an inverse quantizer configured to inversely quantize the residual signals;
an inverse transformer configured to inversely transform the inversely quantized residual signals;
an intra predictor configured to predict a current block from a plurality of neighboring blocks of the current block; and
an adder configured to add the inversely transformed residual signals to the predicted pixels in the predicted block,
wherein the intra predictor comprises:
a weighted pixel calculator configured to calculate 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
a pixel predictor configured to derive a predicted pixel value of the current pixel using the weighted pixel values, and
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 apparatus 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 apparatus 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 apparatus 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 apparatus 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 apparatus 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 apparatus 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 apparatus 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.