Patent ID: 7712664

Claim:
A 2-dimensional code reading apparatus comprising: a dot detection unit receiving an input image that is formed by optically reading 2-dimensional codes, which are constituted by dots, and detecting the dots from the received input image; a code frame detection unit configured to detect a code frame from the dots detected by the dot detection unit, the code frame defining a fixed rectangular region by frame dots arranged in a matrix formation at a predetermined spacing in each of two orthogonal directions, said code frame detection unit configured to determine that a target dot is a corner dot of the code frame when four or more neighboring dots which are located around the target dot and are centered on the target dot are detected and two sets of symmetric dots with respect to the target dot are detected among the neighboring dots; a data decoder configured to read a pattern of the dots arranged within the code frame and configured to decode to reproduce information indicated by the read pattern of the dots, wherein the dot detection unit is configured to perform the dot detection only for a region smaller than a region of the input image.