Patent ID: 7519224

Claim:
An apparatus for preprocessing a page image reproduced from a storage medium in a holographic system, wherein the page image includes a data image and upper, lower, left and right borders surrounding the data image, the apparatus comprising: means for calculating pixel sums for each lines in the page image to select a maximum sum among the calculated sums at each upper, lower, left and right corner in the page image, wherein a pixel location corresponding to the maximum sum corresponds to a border; means for calculating a modified maximum sum using the maximum sum and its neighboring sums, wherein a pixel location corresponding to the modified maximum sum corresponds to a modified location of the border; means for calculating a distortion error between the position of the border and the modified location of the border to determine whether the calculated distortion error exceeds a half pixel; means for determining a compensation location for distorted pixels using the modified maximum sum when it is determined that the calculated distortion error exceeds the half pixel; and means for over-sampling pixels in the data image with reference to the compensation location.