Image encoding apparatus and method of controlling the same

An image encoding apparatus for encoding image data, comprising:

• a reduced image generator which generates reduced image data for input image data of an encoding target by outputting one pixel corresponding to N pixels in the input image data;
• an interpolation information generator which generates interpolation information to specify, from a plurality of types of interpolation methods, an interpolation method of N pixels of interest in order to generate, from the reduced image data, image data having a resolution identical to that of the input image data;
• a lossless encoder which executes lossless encoding of a block in the reduced image data;
• a lossy encoder which executes lossy encoding of the block;
• a selector which selects one of said lossless encoder and said lossy encoder based on the interpolation information corresponding to a block of interest in the reduced image data and causes the selected encoder to execute encoding processing of the block of interest;
• and
• an output unit which outputs, as encoded image data corresponding to the input image data, encoded data obtained by the encoder selected by said selector and the interpolation information generated by said interpolation information generator,
• wherein the types of interpolation methods represented by the interpolation information generated by said interpolation information generator include
• a first interpolation method of restoring the N pixels of interest from one pixel of a reduced image corresponding to the N pixels of interest or at least one pixel located around the one pixel of the reduced image, and
• a second interpolation method of restoring at least some of the N pixels of interest without referring to the reduced image.