The present invention provides a method and apparatus for preprocessing a page image reproduced from a storage medium in a holographic system. The present invention calculates pixel sums for each lines in the page image to select a maximum sum, calculates a modified maximum sum using the modified maximum sum and its neighboring sums, determines a compensation location for distorted pixels using the modified maximum sum and performs over-sampling a data image with reference to the compensation location of magnified pixels, to thereby compensate the data image with high precision in sub-pixels.