Image encoding apparatus and method of controlling the same

摘要

This invention generates efficient encoded data to restore original image data from reduced image data. An input unit inputs block data of 2 × 2 pixels from original image data. A converter generates reduced image data having a size smaller than the original image data by sampling one pixel data at a preset position in the input block data. A generator generates encoded data to restore three non-sampling target pixel data in each block data so as to restore the original image data from the reduced image data generated by the resolution converter. To do this, the generator determines whether all non-sampling target pixels in a block of interest are restorable from a sampling target pixel in the block of interest or from sampling target pixels in three blocks adjacent to the block of interest, and generates and outputs three kinds of additional information based on the determination result.