1. An image compression apparatus, comprising: a processor configured to: generate a reduced image with a reduced resolution by sampling an input image, divide the reduced image into blocks, calculate pixel value errors for each of the blocks, a first pixel value error of a first bock being calculated between the first block and the rest of the blocks, and the pixel value errors comprising the first pixel value error, select, as a representative block, a block of the blocks having a smallest pixel value error among the pixel value errors, determine filter information comprising an interpolation coefficient with respect to the representative block based on the input image and the reduced image, and generate a bitstream by coding the reduced image and the determined filter information.