Patent ID: 7481369

Claim:
An apparatus having a photodetector with a plurality of pixels arranged in at least one dimension and designed to optically pick up an image of an information code by the pixels of the photodetector, the apparatus comprising: an establishing unit configured to establish a preliminary correcting region on part of image data based on the picked-up image; a preliminary correcting unit configured to; provide a correcting variable that represents a shift amount of the image data; and preliminarily correct the part of the image data within the preliminary correcting region based on a value of the correcting variable; a determining unit configured to determine whether the preliminary correction of the preliminary correcting unit is proper based on the corrected result; and a correcting unit configured to, when the determining unit determines that the preliminary correction of the preliminary correcting unit is proper, correct the image data based on the value of the correcting variable, wherein the image data is composed of gray levels of the pixels of the photodetector, the value of the correcting variable represents a number n of pixels corresponding to the shift amount of the image data, and the preliminary correcting unit is configured to preliminarily correct the gray level of each pixel of the photodetector within the preliminary correcting region based on the value of the correcting variable.