Patent ID: 8867626

Claim:
A processor-implemented image decoding method comprising: executing a variable-length decoding step, by a processor, to perform reverse variable-length encoding processing; executing a reverse quantization step, by the processor, to perform reverse quantization processing of data handled by the variable-length decoding step; executing a reverse frequency conversion step, by the processor, to perform reverse frequency conversion processing of data reversely quantized by the reverse quantization step, thereby decoding difference in prediction values of a target block to be decoded; and executing an intra prediction decoding step, by the processor, to perform intra prediction that includes acquiring a decoded image by using the difference in prediction values of the target block to be decoded; wherein the intra prediction decoding step predicts a target pixel to be decoded by use of at least two reference pixels, wherein each of the at least two reference pixels is a decoded pixel located in one of a same row or a same column as the target pixel to be decoded, otherwise when a reference pixel is not selected from among decoded pixels, the intra prediction decoding step uses, as a pixel value of the reference pixel, a pixel value is calculated based on any of an average value, a median value, a minimum value, a maximum value, a linear interpolation, or a non-linear interpolation of a set of pixels belonging to a same row or a same column of decoded adjacent blocks.