Two dimensional code reading apparatus

摘要

A two-dimensional code reading apparatus including a CCD sensor that captures an image including a two-dimensional code attached on an article being conveyed, for example. The two-dimensional code is formed as a matrix of light and dark cells, and includes at least two orientation symbols at corners of the matrix. Each of the orientation symbols is geometrically defined so that when a scanning line signal of the CCD sensor is binary-coded into a sequence of scanning line pulse signals, they show a given frequency component ratio. The two-dimensional code reading apparatus identifies an orientation of the orientation symbols based on positions of the pulse signals showing the given frequency component ratio in the captured image to determine positions of data cells in a data field of the two-dimensional code adjacent to the orientation symbols for decoding code information indicated by the data cells.