1. An intra prediction method of predicting pixel values in a prediction target block on the basis of a plurality of neighboring pixels adjacent to the prediction target block, comprising the steps of: receiving and decoding encoded video information; determining a target boundary by determining a plurality of boundary pixels indicating the target boundary in the prediction target block on the basis of the decoded video information; determining a plurality of prediction target regions into which the prediction target block is split by the target boundary; and performing a prediction on the plurality of prediction target regions on the basis of different neighboring pixels out of the plurality of neighboring pixels.