A video decoding method performed by a video decoder, the method comprising: obtaining an image information including residual information from a bitstream; deriving an intra prediction mode of a current block; generating a prediction block of the current block based on the intra prediction mode of the current block; selecting a neighboring block of the current block based on Sum of Absolute Differences, SAD, between said prediction block of the current block and the neighboring block; deriving correlation information based on a reconstructed block of said selected neighboring block and a prediction block of said selected neighboring block; deriving a modified prediction block (P') of the current block by modifying the prediction block of the current block based on said correlation information; and deriving a reconstructed block of the current block based on said modified prediction block (P') and a residual block derived from the residual information, wherein the correlation information comprises a weight per block and an offset per block, and wherein the weight per block and the offset per block are derived through Least Square Method, LSM, with respect to a respective value of reconstructed samples included in the reconstructed block of said selected neighboring block and a respective value of prediction samples included in the prediction block of said selected neighboring block, and wherein said modified prediction block (P') is derived based on an equation as below: P ′ x y = αP x y + β where P'(x,y) denotes a modified prediction sample value at coordinates (x,y) included in said modified prediction block, P(x,y) denotes a prediction sample value at coordinates (x,y) included in the prediction block of the current block, α denotes the weight per block, and β denotes the offset per block. obtaining an image information including residual information from a bitstream; deriving an intra prediction mode of a current block; generating a prediction block of the current block based on the intra prediction mode of the current block; selecting a neighboring block of the current block based on Sum of Absolute Differences, SAD, between said prediction block of the current block and the neighboring block; deriving correlation information based on a reconstructed block of said selected neighboring block and a prediction block of said selected neighboring block; deriving a modified prediction block (P') of the current block by modifying the prediction block of the current block based on said correlation information; and deriving a reconstructed block of the current block based on said modified prediction block (P') and a residual block derived from the residual information, wherein the correlation information comprises a weight per block and an offset per block, and wherein the weight per block and the offset per block are derived through Least Square Method, LSM, with respect to a respective value of reconstructed samples included in the reconstructed block of said selected neighboring block and a respective value of prediction samples included in the prediction block of said selected neighboring block, and wherein said modified prediction block (P') is derived based on an equation as below: P ′ x y = αP x y + β where P'(x,y) denotes a modified prediction sample value at coordinates (x,y) included in said modified prediction block, P(x,y) denotes a prediction sample value at coordinates (x,y) included in the prediction block of the current block, α denotes the weight per block, and β denotes the offset per block.